I have been researching building foam wings - I have a set of cores I am going to build.

I am wondering if you can cut with one airfoil, but use different sized stock for the leading edge and sand appropriately?

Separate pieces is certainly an option, there are threads where people cut single airfoils in parts to install the ribs.

I am curious what you mean about having a 'thin tip'.

DEFINITELY read over Isaac Najary's build threads - he doesn't cut or sheet the foam, but there is a lot to be learned about installing the edges, tips, and sanding, etc.

Looks like fun! Enjoy!!