I am very fond of revolvers that shoot semi auto ammo. Therefore I have several N frame Smiths that are chambered in .45 ACP and several have an extra .45 Colt cylinder. The cylinder walls do look thin compared to other N frames, but the 45s are the biggest bore that you can get an N frame in so the cylinder walls are going to look thin by comparison.
I do not give any M25 or 625 a steady diet of high pressure ammo, however one does not have to as the standard Semi WC or flat point ammo will do just fine for just about anything that does not need real penetration(think Brown Bear).
I do use just about any major brand for .45 ACP including +P. +P is not what it used to be, sometimes not giving much more velocity than standard loads from the same maker.
Buffalo Bore makes some real screamers in ACP and .45 Colt, but I only use them in Rugers or carbines, but I would not worry about shooting a few of them out of my N frames if necessary.
I do regularly use Speer .45 ACP 200 GR +P FMJ flat points regularly in my 325 NG, the barrel is so short(and the bullet lighter) that the pressures just do not build up as much as in a longer barrel, and that round is a proven stopper of both 4 and 2 legged varmints. I prefer the flat point for most applications that the ACP and Colt round are used for. You have to have some serious velocity to get an HP in those calibers to expand, I would rather have the penetration and put the slugs where they need to be for the desired effect. I do use HPs in my .45 ACP pistols and do not worry about the higher pressures of the +P loadings as I just replace recoil springs regularly(although the above Speer load is a really good one for autos also).
Also I do not like to depend on expansion for effect when the stakes are high(serious social interactions), rather I prefer deep penetration CNS or pelvic area hits. Crack the pelvic cradle and that person is going nowhere anytime soon, and I have never seen anyone who could fight through the incredible pain of such a hit to keep on shooting, hope I never do either.