Annular Ring for early converter to later crank info???

Howdy all, cosgig here! I'm coming up on doing my engine swap, but I need an annular ring spacer that goes between my early torque converter snout and my later 340 crank!! I know I can buy one from T-Flite Patty, but with a retired machinist with a machine shop living next door, I would prefer to save the money and have him make one! I have a couple questions to anyone who can provide any info....

(1) What material are they made of?
(2) Does anyone have a picture of one?
(3) Can anybody measure one up? Things like the ID, OD and width?
(4) Is there a chamfer on the outside to make it easier for the converter to slip into?

Any help would be much appreciated, and thanks for any and all replies!! Geof