Okay, we're closer, but going back to my original problem, the issue with the threads showing on my front wheel when using a 12mm nipple comes not from the spokes being too short, they are the correct length, but rather because the spokes are threaded very, very long at 13.74mm. So even when fully tensioned and the top of the spoke level with the top of the nipple, threads still show at the bottom...hence the need for a longer bored nipple to hide/cover the extra threads. Unfortunately, those those longer nipples general come with more thread, not the same amount of thread as the 12mm that works perfect with my rear wheel with more standard 9mm threaded spokes. I was finding it difficult to find nipples that worked for both wheels, for aesthetics sake.

Anyway, I found some 16mm Wheelsmith brass nipples with 8mm of threading (supposedly) that approximate the original aluminum ones (15.5mm with 8.5mm of thread).

Thank you for hashing this out with me and for the counterboring tip (all)...I'll keep it in mind if these nipples don't work out.