I recently groud out the smallest dies(14awg) that came with my harbor freight H crimper.
Exactly how much to file/grind out was trial and error, and I missed it on the 2 awg, going a smidge too far, and not quite far enough on 6awg lugs.
Some folded aluminum foil on the 2awg leaves me a beautiful earless crimp, but the 6awg still pinches some ears.
I really wish one could just buy the proper size lugs, But I'd be happy with just a template to scratch into the improperly sized lugs and then grind them out to the correct size.
I've been using the thick walled rig terminals from Genuine Dealz and they are well made.
Never considered making my own lugs from copper pipe. But will consider it in the future.