Studs and nuts, or set screws/bolts? Both my BSAs have studs and nuts on the fork bottoms - already there, not mine.
I always use studs washers and nuts where I can as the fewer times things come out of critical 'oles the better.
I'll happily make things in metric if that means stealing less metal at the receiving end! But I'm also a big fan of 5/16th 24 and 3/8th 24 UNF - a very useful pair of fine threads and easily obtainable everywhere your side Lannis, in good quality as you say. Just means carrying one extra, AF, spanner from time to time. Per MikeN's comment, I use WW very rarely except into alloy as the minor diameter is so small - which is why BS'Fine' came about.