from what I remember & have applied from ready though the zillion posts here
scales - wood or horn about 1/8" thick each will work well
wedge thickness - this is the thickest part at the top of the wedge - measure the blade thickness at the point were you want the blade to rest in the blade, this is dependant on the grind by about 2 thirds the spine thickness maybe right
wedge angle - wedge angle should get the scales to be about 1/4" wider than the thickness of the tang at the pivot hole when the wegde is pinned &
some wedges can be wedged vertically as well as logatudinally if the tang is tapered vertically also.

pitty about the orginal scales they look great with the inlays, did they only break at the pivot as you may be able to use them on a shorter blade later