If you for go
http://www.kayewood.com/tips/bindings.pdf she has a complete explanations of how to do this. I think with a 2.5 cut you need about a 3/8 inch seam allowance to get it to wrap around correctly. If you just increase your seam allowance a bit it should work really nicely. (Try it on just a short distance of what you have already sewn to see what works best.). Your binding strips should be cut 6 times the finished width, for a double binding (except for a finished width of 1/4). Hope this helps.