Paul,
Try this grind height calculator to check your blades are the right width and thickness for a given wheel size. It does a great job of predicting where your grind line will terminate.
http://bimjo.com/free/hg_calc.xls
Until I found this I also had the same problem with blades being too wide, and then having to stretch the grind up the blade so it looked right.
Cheers,
Steve