scarfs can be a bit challenging. 

like a lot of folks who make skarfs i use a little tool that i made that works with a disk sander....i also use a custom made mitre box.  but in a nutshell, it has the angle built into it and holds the strip/guides the strip to ensure consistent scarf joints.   on the belt sander, i set up a guide so that i insert the strip into the guide and it quickly (60 grit spinning wheel) sands the strip to ratio of 1 to a 8 (so the scarfs are about 2 inches long for a 1/4 inch thick strip.  i also have a mitre box i built that holds a strip tightly and has 90 degree cuts, 45 degree cuts and 1 to 4 and 1 to 8 cuts all set up.

on making the wood more bendable, i would try a heat gun before i would go to stream.  heating the wood makes it more bendy and is easier than steam.  you just need to ensure you don't burn the wood.  but for strip building, having a high quality adjustable heat gun is a great tool to have.   practice of a scrap strip to get the hang of it.

h

I got the scarfs done without too much trouble, but I'm also having some difficulty getting the sheer strips in place on my WD 10. I've got the wood splitting around the nails because of the tension with the curve.

   Nails......? 

Most strippers use staples or hot glue to hold the strips to the forms.  I'm thinking you are trying to bend the wood too fast, not using enought clamps or tape, or not heating the wood before bending. 

OR it sounds like the bend is across the width of the strip, like it was rising too much to meet the bow.  I had similar problems and took the easy way of changing the strip pattern to a less agressive, more fill in way. 

They are actually small brads, but I will try staples. The tricky bit seems to be giving yourself enough overhang of the hull while still getting enough of the fastener into the form to hold it on the initial strip.