Anyone gone from a PO 2500/8500 42mm, to the 8800 39.5?

Just curious if any of you have gone from old school Mk1 or Mk2 42mm PO to the 3rd PO and the 39.5?
Probably won't part with the Mk1, but I've never been as attached to the 8500.
Plus.... are all the old 20mm straps redundant on the new 19mm, or do they still squeeze on in.
NATO, leathers etc. Assume bracelets won't.

I got the 39.5, when I bought the Nato from the OB they actually sold me a 20mm, a soft leather strap might fit as well but anything solid wont

Well, not exactly but from 45,5 to the recent 43,5 (twice in two years..) to finally understand what was wrong and how great 39,5 is, not only sizewise. My wrist measures ~17,5 cm, the small version is perfect for me. Some might not agree but I find it pretty balanced, size and weightwise.
I swapped the Bracelet for a 20mm Nato this Summer, no problem. ( see size and weightwise 😀)

A size comparison, not against the 43,5 but next to other watches you might have handled/held/wore:

Thank you gents, so the 20 NATO work, but rubber probably won't, wondered about the Iso, and bracelets definitely won't.

It doesn't look as small as I expected, especially next to the Sub where it looks pretty much the same in your first pic, but slightly larger next to the no date. Is that pre 14060 a 5513? Size wise it fits you perfectly. Both my PO are 42 and the 2500 looks right on me, but I sometimes look down at the 8500 over the years and think it may be too big, despite them both being a 42. The 8500 on NATO looks fine, but on the bracelet I still don't wear it that much. Your wrist size is pretty close to mine, just under 7 inches, which must be around that in cm. Thanks for that. It doesn't look remotely out of place in that line up as the 'smaller' model.