I'm not denying that the engine is hard on oil, but with short intervals and good oil they seem to do fine. It is, however a particularly poor canidate for brand "x" bulk oil, or quicky-lube places (the wrong oil or not changing the filter would really screw you on a sludge prone engine).
A decent Group II+ oil like Chevron Supreme or Pennzoil changed at 3k would be pretty safe, though I personally would want to do at least occasional oil analysis too. For a little extra piece of mind, running a $4-5/qt Group IV or PAO synthetic wouldn't be a bad plan either. Nothing wrong with the AutoRX suggestion also.
I wonder whether a colder t-stat, different fan thermal switch, or an oil cooler would help any...but since the problem seems relatively minor it probably isn't worth it.
I did find the comment about the person whose engine died from lack of pressure after the oil warning light came on amusing. One would think that they would have known that the Service Engine Soon/MIL light has utterly no connection to mechanically conditions such as overheating or low oil pressure!
I really don't want to seem like I'm bashing amsoil, but I wonder if since this engine has a historty of the problem, the amsoil warantee wouldn't apply?