HEY GUYS,
I'm not sure of the exact sizes off hand, but I ordered a set of spokes for my vintage 18" front rim from Buchannan's, and it turns out I may need to order another set.

The reason being that I ordered straight spokes that are not tapered down; they gave me two choices for the nipples; larger or smaller, and I chose that larger ones on their advice. They told me I could easily drill the holes in my rim out. Looking at it now, it does appear that I will be better off ordering a second set with tapered threads which will use the smaller nipples.

That being said; The first set I ordered were custom made and non-returnable, so if anyone is interested, please let me know. (Please send me a PM...) I'll gladly send them to you for my cost. They should work perfectly with any of the modern 18" rims.... They are stainless, with nickle plated nipples I believe. I'll get the exact specs if anyone likes.