Hi Wayne,
I printed a 12mm dia screw x 50mm and 3 nuts x 20mm long with a 2mm pitch 90 degree form separately.
The clearances 0.15/0.2/0.25mm.
The 0.25 nut no problem.
0.2 nut required working along the screw a couple of times but fine.
The 0.15 would only go onto the screw about 12mm with a lot of working back and forth.
I think the 0.15 clearance would have worked with a shorter nut maybe its down to shrinkage.
Anyway glad it works.
Cheers
Barry