I like the lead spacers, reconsider keeping it, you don't put the end of your razor in your mouth do you? You should be okay then if you don't.
Well if you still want to make a wood spacer get a piece of 1/8" thick wood that's around 1"x at least 2-3 inches.
I use a belt sander to put the taper on the wood but you can just use a sanding block if you want.
Taper it down to the same "wedge" as the old one, re-pin your scales to it and then sand it down to match the shape when it is in the scales.