long may you strum!
I think I already did!
Thanks Jim and everyone for comments - so far I've had no problem retuning the EXPs and they don't feel too plasticky, but I'll definitely try some uncoated strings eventually.
And I don't have a problem with reasonably heavy strings, at least not yet. (I play the bass quite a lot, which helps.) But arthritis runs in the family so it's likely to hit me eventually.
Quick followup - with the EXP16s, the action on my L25 is very low, with a little nearly-buzzing on a couple of capo'd strings. It's not actually a buzz, just a quick rasp when the string is plucked really hard, so it's not a problem.
But I was wondering - if I upped the guage to 13s, would that lift the action a little? And would there be any other adverse effects on the guitar of using heavier strings?