Ive only done one or two blade mods so someone might have better advice. I used a bench mounted grinder on one when I modded the spine shape. Only do a very little at a time, keep the blade cool by dipping it in water every couple of seconds. If you don't you run the risk of killing the temper. You should be able to do any finishing work with a smooth file and some wet & dry.
If you are looking to change the edge shape (like flattening out the belly) then I have just done it on some bench stones. Unless you work so fast the blade becomes to hot to handle you shouldn't be in danger of doing any damage to the temper.
We want to see the results as well.