Avoiding cooler nighttime temperatures will ensure strong joints and speed up the build process. A small heater should suffice through September. I like the gray PVC clamp on work lights from Home Depot. They are cheap and durable. You can’t have too much light. If you haven’t browsed the Off Center Harbor site and videos you should. Russell Brown’s epoxy series alone is worth the subscription. Good luck with Skerry. Is it destined for the Small Reach Regatta?

 >> How much space is recommended? <<

Enough to hold the finished boat plus at least two feet all the way around. Less can work, but it takes planning. You don't want to be doing a belly rub with the epoxy you applied five minutes ago. Don't forget to leave room somewhere for the shopvac. If you plan to use non-handheld power tools (drill press, tablesaw, etc.) you'll need room for them too.

>> Is overhead lighting sufficient? Or is it a good idea to get lights that can be moved around? <<

"Overhead lighting" can encompass a lot of things. A single overhead bulb is not going to cut it. My single car garage has two 2-tube flourescent fixtures overhead and that works fine for my build. I have some portable worklights but haven't had to break them out yet. Probably will when I get to finishing - a glancing reflection reveals blemishes to fix before your adoring public has a chance to see them. Cyclone is right: you can't have too much light.

>> I know temperature control is crucial... <<

Temperature control is not crucial. Working with the temperatures you have and the temperatures your epoxy can handle is what's crucial

Start with the daytime temps: if it's warm you're going to want to be using slow hardener because you want to get a decent amount of work done before your epoxy starts to gel. If it's cool you'll want to use a fast hardener because the gel times become ridiculous* if you stick with slow. Look at the recommended temperature ranges for the hardeners and follow those guidelines. Don't buy a million gallons of slow hardener if you think your build might extend into the fall and you'll need fast.

So now nighttime comes and everything cools down. That's somewhere between a "so what?" and a good thing. The cooler temps will slow down the cure so if you need to apply a second coat of epoxy you won't have to sand the first one quite so soon (use the fingernail test - if you can dent the epoxy with your fingernail, it doesn't need sanding.) Of course if you want it to cure fast ("I can't wait to varnish this sucker!") then you'll want to keep it warm or apply heat. But most often you'll appreciate the longer "second coat" time.

One more recommendation: Get yourself a wall (or garden) thermometer and a wall clock. As epoxy is temperature sensitive you'll want to know the temp in your work space. That isn't necessarily what's outside or what the thermostat might be set to. The clock is so you can time how long you've been stirring your epoxy and how long it's been since you mixed it without goobering up your watch with your epoxy-covered gloves.

Regards,

Chenier

* What's ridiculous? My build is in a (usually) unheated garage. I did some epoxying just before Thanksgiving when it was about 40ºF. With slow hardener because I'd bought a million gallons. It was just barely starting to gel the next afternoon. Went away for Thanksgiving and it was fine when I came back. After that I switched to fast hardener and a couple of space heaters for the winter.

You can't have too much light, unless it's harsh, undiffused light coming at you from low angles.  If the walls of your space are dark, hanging some light-colored drop cloths or some such along the walls will help diffuse the light to lessen the contrast of the shadows.  A headlamp will help with measuring and other close work where shadows would be problematic.  A pair of cheap reading glasses can help with the close stuff in iffy light, even if you don't normally need to use such things.

Leave room for a "moaning chair", a comfortable place to sit where you can view the work with a cup of coffee (save the stronger stuff for after you plan to use tools), building manual in hand, to think through the next step or to puzzle through some difficulty.  Kind of goes with the "measure twice, cut once" mentality.

Remember to have fun.  It helps if friends and family will drop by to help (there'll be times when you could really use extra hands, providing they are patient and obedient) or just hang out.

Some sort of device to play music would be good, but remember that there will be a lot of dust from sanding and your gloved fingers will sometimes have uncured epoxy on them.

Try to arrange things so that you don't need to take phone calls while you've got a pot of epoxy kicking off or are otherwise in the middle of a step which requires concentration from end to end.  Epoxy and expensive smartphones are a bad mix, anyway.

.....Michael

I started my Passagemaker in a spacious garage and then switched over to a much smaller single car garage when I moved house. TBH I prefer the smaller one because it is much easier to keep clean and everything is right at hand.

The one thing I don't see mentioned here is having a dedicated bench or table to keep tools, prints, supplies and then another area for the epoxy work. 

Regarding the lighting make sure the lighting is even on both sides of the boat whether that means fore/aft or port/starboard. Unless the lighting is directly overhead and diffused you might miss something that you would have seen if it was lit from the other side.

If you lived in God's Country (Minnesota) Menards has a $10 LED 1200 Lumen portable work light from Smart Electrician that is awesome and crazy bright. It has a stand or you can hang it. I say it outsines my 3000W halogen work light and much more durable and won't make you feel like a rotisserie chicken working underneath it. I'm sure you can find it somewhere out there. Full disclosure that it not the most sexy lighting for taking photos of your progress. You want old fashioned incandesant for that.

Like Chenier said just work around the temps you have. Do epoxy work when it is warm to hot. Sand and plane when its cooler.  Although from the research I did it is not advisable to epoxy under 55 degrees F. IMO, It's one thing for a clear coat on the boat's topside for instance in less that optimal curing conditions but for an epoxied seam that holds your boat together and keeps you out of the freezing North Atlantic make sure that gets done in good conditions and to the letter of the law of the manufacturers' instructions.

Have fun!

-Patrick