Quick question:

I've got a long sleeved coat of wedge-riveted/welded mail from Zeughaus that's supposed to have 9mm rings (no idea if ID or OD) but it's not long enough on the thighs, so I'm thinking of buying some of those 20cm squares of mail from GDFB UK and riveting them onto the skirt. However, they're 8mm ID. Does that even matter, or will this end up being a terrible mistake?

Different ring sizes are used historically, generally with lighter rings on the skirting and sleeves and heavier over the body. Erik Schmid's examination of the Wallace A7 shirt gives evidence of shirts being patched together from different pieces of mail.

Yep, it's perfectly authentic, but you have to be aware that it will look quite different. Especially if steel colour will be different too.

Cool, thanks guys! I think I might know what to do with my Christmas monies. :)

I used 9MM rings to seal up my tie in the back 8MM chausses to convert them to full leg ones and it worked just fine, I bet they did use this stuff in period anyway as I've seen examples of mixed ring sizes on hauberks and whatnot.