Did you lose the entire fingernail? I forgot to ask. I've never heard of that happening from mail, nothing beyond nicks and abrasions.
To start with, a couple good reads:
http://www.myarmoury.com/talk/viewtopic.php?t=19189http://www.myarmoury.com/talk/viewtopic.php?t=26877 (this one is very short)
Sorry if I'm asking questions I asked and/or you answered at DoK - I was overwhelmed and don't remember much of the mail conversation since it was in-between talking to visitors...
Are you wearing the round head of the rivet on the inside or outside? The round head should be on the inside, not outside. It's like wearing a shirt "inside out", that is actually correct.
At DoK, were you comparing wedge riveted indian stuff with round riveted indian stuff? The difference in quality can have as much impact as the difference in the actual type of construction. Remember, we're paying really cheap labor to places that don't really care if it falls apart on us or not. There are plenty of issues with it, but to solve those issues will take work, or a couple thousand dollars - literally.
I don't remember the exact transition period and can't find the link that had the crossover info, but dome riveted mail was the most common type for a long, long time, starting with the romans (or before?). For your period, it would have been dome riveted. Wedge riveted is much later, towards late transitional or early "full plate" harnesses. Those that would have had it earlier on in the transition would be people with more financial standing and constantly staying at the forefront of armor evolution.
Tailoring your mail may help some. Having enough mail to flop around freely makes it easy for it to scratch stuff up (skin or cloth). If the round head of the rivets aren't all facing inward or outward, pick an "inside" and peen down the rivets that are rough to the touch. It doesn't take a big hammer or an anvil to do it, just a small, solid metal surface and a light hammer.
You can also look into either edging, or lining the mail. When I finish tailoring my hauberk, it's going to be lined so that it's easy to get on and won't rub or tear much. Same concept as sewing an arming cap directly to the coif, as I did with mine, and as the good Dr Metz seems to have done with his (from what I could see). I haven't seen anything to prove or disprove if mail was lined historically, but surviving stuff is so limited, and garments being natural fibers, it wouldn't survive for 1,000 years. There *IS* some historical artwork that shows what looks to be leather trim on it, and to me, leather trim makes the most sense as what they used to sew the lining onto the mail with...
The flat rings are more abrasive because they have a hard, angled edge. Round ring riveted is less abrasive because it's a curved surface. Solid vs riveted, the lack of rivet will make it less abrasive, but the ring itself comes down to being round or flat. Riveted will always be flattened around the rivet itself, too.
The "softest" mail you can get is round ring, welded mail. There's no rivets to rub, and no corners of the rings (when looking at a cross-section). The only one I know who makes that off the top of my head is Master Knuut, who does make it to your size so there's minimal / no tailoring needed, but I don't think it has any historical basis whatsoever. I've only seen it strictly in SCA context.
It comes down to a question of do you want something soft, that doesn't wear as quickly on your arming garments, or do you want something that is more historical, but has more wear-and-tear on the arming clothes. Historically, arming garments would have been replaced as needed, and the concern was more on living and being protected, rather than frayed or torn threads. If the threads did tear or fray, put a drop of super-glue or seam glue on them, and it will help keep them from fraying or pulling out more. I've worn my pourpoint once, it tore, and it got sewn. I've got a few things fraying on my arming coat that is only about a year old. They won't last forever, and aren't designed to - just keep it in mind as a wear and tear, replace as needed item - just like brake pads or tires on a car.
Hope that helps some.