I recently completed a trade for a Chopard Mille Miglia (2005 vintage me thinks). Beautiful, cool watch (review coming soon), but curse you Chopard for using 21mm lug widths! My new to me MM had a decent but nothing special black rubber strap (not the original). I wanted to swap it out for something nicer. Plus, the buckle on the strap was quite "pointy" and tended to dig into my wrist. So, having read on other posts about 21 vs 20 vs 22 lug widths and what to do about straps, the general consensus was that squeezing a 22mm strap in there would be no problem. Now, yes I know you can get 21mm straps but they're not that common and I happened to have a 22 on hand to try. With trusty strap changing tool in hand I proceeded to try to install my 22. Turns out the edges and point of the lug on the Chopard are quite sharp (to leather straps anyway). Ruined the edges of my strap. Rats. Pulled a 22 off an old watch I never wear anymore to see how that strap would fit. Same issue, the edges/point of the lugs act as mini lathes/planes - scrape the edge coating right off the leather. Double Rats.
Took the watch to RightTime here in Denver. They measured the lugs to be sure, yep 21mm. We then talked about strap options (no 21s in stock). I mentioned that the lugs were hard on 22mm leather straps and maybe we should try 20mm. They commented that that's not the best idea as a strap that's too small doesn't provide enough support and the spring bars then take all the force exerted on them and can fail. Never heard that before but this a respected watch shop so I didn't argue.
Anyway, in the end we found a great new (they'd just got a few samples in) Toscana strap. 22mm black rubber but with a brown leather (alligator patterned) inserts. Really nice looking, comfortable, sets off the watch nicely.
So, out of all this I learned that the watch tolerates 22mm rubber fine (squish-ability) but not 22mm leather. And that Toscana makes a nice rubber/leather combo strap.
Now, a question for any of you who've read this far, are there other strap makers that combine rubber and leather? I'd like to get a couple of different styles to wear as the mood strikes.