Cutting Foam Wingtips
 

OK, I'm stumped. Cutting a core is easy enough to figure out the basics of. I have designs on building a dropbar system. I have no idea how you go about cutting wingtips though.

Say you want a straight wing with rounded wing tips. Can you cut them via hotwire or do you have to sand them by hand? Should I just frame up some balsa wingtips instead?

Second question regarding wood sheeting said foam wings. I was planning on vacuum bagging them, but I'm curious what is a good glue for skinning balsa to blue foam?

Thanks!