Why would a RR affect engine temps??
It doesn't. The engine generates far more heat burning gasoline than the stator does generating electricity. Simple physics.
It is a stretch to suggest the stator raises oil temperature above what the engine does no matter what the regulator was doing. Other bikes have a dry stator not bathed in oil that use the same regulator (Honda CM400 ex) and if the stator actually got THAT hot it would burn up in no time.
Interestingly enough these Honda bikes don't suffer from stator failures and their SDG regulators never fail no matter how bad the connections get. So another myth is busted that corroded connectors break stator or regulators. Corroded connectors just make it hard to keep the battery up but don't "kill" regulators.
Using an overkill regulator isn't going to hurt anything as long as it's wired properly and mounted securely. The costs for the regulator is much higher than the SH-232 or SH-532 and there is the matter of a wiring harness to contend with. But to each his own. I've moved 300+ SDG regulators in the past few years and I think they are working fine these days.