Even before I did the burnishing I've never had a bow lift a splinter. I know that sounds obsured. I've had bows come in underweight and I've had a couple explode. But making sure your back is baby butt smooth is an important step:)
I can't credit bnurnishing, but I haven't broken many bows, either.  My first 20 or so all survived.  But I sure made a LOT of kids' bows back then!
So, I'm late to the party, but as an old hat, I am both learning and noticing things on your build.  A few comments ok?
Gopod to know ipe can be bent.  I gave up pre-bending tropicals, but will try again.
I am NOT good at the thickness layout thing where you scribe the line.   I have to use a caliper or homemade spanner for initial layout.  Probably because I mostly work with lumpy sapling staves of small diameter.  But, any tips?  
And, also because of the 3" dia sapling thing, I usually just try to start with straight bark on a tree, and lay the bow out following the crown more than the grain.  Any tips for following grain on a white, non-grainy wood like V-maple?
Burnishing helps.  I learned to do it before tillering on some elm staves with pin knots and stick-ups, and it helps.