This is my first re-handling so maybe you could answer a couple of questions for me. Do you rasp of enough material so that the head slides over easily without pinching the kerf cut closed, or do you make a tight fit that closes the kerf, and then just force it back open with the wedge? Also, how far beyond the bottom of the kerf cut do you try to seat the head?
I think the way it's suppossed to be done (and the way I try to do it) is rasp off enough so the kerf just barely closes...then wood wedge, then metal wedge
What usually happens is I play heck getting the right shape (there's a lot of wood to rasp off on new handles for old heads, and sometimes they're not wide enough one direction and too wide the other), I pound the head on tight (tight kerf), and then gently tappy-tap the wedges in...results in a good tight fit, but more than the average amount of cursing
I try to seat the head at least a 1/4 inch below the kerf bottom...sometimes it works, sometimes it doesn't. (I have an old youth axe head I rehandled at 10 degrees F with the help of a torch...it still has 1/4" of kerf exposed) Usually there's a shoulder built into the handle that I pound the head tight down onto...and I try to have excess handle above the head to cut off.
Really the worst situation is if you rasp off too much, and don't have a tight fitting handle.
Dive in and enjoy it!
Now for the unsolicited comments...
Use a brass hammer...maybe a heavy wooden mallet...more forgiving, and easier on the metal head if you have to get it off to readjust
If the head is symmetrical make sure to put the wider hole up
Wide metal wedges are the cat's meow for heavy heads...but good luck finding them
When I say "pound the head on" I mean hold the handle and smack it on the ground, letting the weight of the head drive itself on...not with a hammer
Rather than a vise, I grab the handle in one hand, tuck it under my armpit, lay the end on a bench, and rasp with the other hand...but if I had a woodworking vise I'd use that
Keep all your wooden wedge pieces...all of them. I try to fill any and all voids on the top of the head.
Sometime you can center the head on the new handle, and trace an outline as a rasping guide.
Cheers!