comment on item 1 only..."it depends"...really stiff mylar sails are rolled, but normal large sails are first flaked, then rolled, but the initial flaking I always tried to put the flakes at different spots in my 150 genoa sail (and even from opposite sides)... so a fold is not at the same place for it's entire life...for me on my dory sail, it's small enough that I likely will leave it rolled around the spars all the time not being used..plus it's so new that it is very stiff...more reason to roll not fold...just my take anyway

Curt

Eric,

I cannot speak to your question about the spars, but I've stored my sails folded for a lot of years without any noticeable harm.  Probably better not to fold them, but for those of us without a sail loft that's not an option.  Paying a sailmaker to store your sails in a loft is unlikely to be cost-effective.

Cheers,

Dick

   Eric, 

Rolling your sails is a great way to store them. Back in the 70s, racing Snipes, I knew a fellow that would take home his sails and lay them out in the attic, but that is a little exstream.

Wash them off, especially if you have been in salt water, and roll or fold them. The most important thing is to store them where there are no mice! Mice love the dacron for their nests. I have left nicely rolled sails in the boat in the garage over winter only to find a bunch of nice holes in them. Now I make sure all my sails are in the basement - guarded by three cats!

Joel

   I forgot the flex - all good masts flex, be they wood, aluminum, or carbon fiber. A flexig mast, and or spar helps depower the sail in the gusts, and then automatically straightens to power the rig back up in the lulls. You did not mention which type of rig you are sailing, but for most rigs flex is good.

racing dingies and skiffs use the flex to power wnd depower with the gusts. We also use shrouds and spreaders to initiate the flex and to limit the extent of the flex. Can get a little complicated. Leg-o-mutton rigs with a sprit are looking for the mast to bend in the gusts to spill some wind and "twist off" the top of the sail.

Joel

   On question 2, I agree with Joel above and would like to addon with his implied "it depends."

You mentioned a yard... lug rig? On lug rigs, the mast would ideally not flex at all in a gust. This only makes the sail more "bag-like", less "sail-like" and catch additional wind and inefficiently to boot. 

On rigs where the mast is designed to bend, the sailmaker accounts for this, but can only do so to a point. Mast bending farther than the sailmaker accounted for and the sail also becomes more "bag-like"

As to birdsmouth vs solid; a birdsmouth with the same amount of material will be stiffer and stronger and necessarily have a bigger diameter. If given the same diameter, the birdsmouther is slightly less strong and stiff but considerably ligher.

 On sails, with woven Dacron sails, the practical method is to fold them.  Just don't crease them hard and repeatedly in the same spot.  On my big boat's main, I'd stretch the sail out on a clean lawn, then Z fold it starting at the foot and working to the head.  Then I'd loosely fold/roll it from the clew to the tack. That way, the tack is on the outside to shackle on, unfold it to the clew attachment, and the head would be ready to shackle to the halyard.

I've always had aluminum masts, even on the old Sailfish, so I have no great experience with wood spars. Whether a relatively more flexible spar is desirable will depend a lot on the rig and which spar.  I'd think that lugs and gaffs, since they have a tendency for the head to fall off anyway, don't really want or need extra flex in the mast to add to that trend.  Conversely, for marconi and leg o mutton sprit rigs, you may want the mast flex under load to help unload the head in gusts.  

   Thanks Gents.

ev