In the primary... just a good 10W40 with low moly, like Castrol GTX or Valvoline 10W40. Even higher moly oils will work fine. I've used the following oils in my primary (1994 Low Rider), with no problems at all...
Valvoline 10W40
Napa 10W40 (same oil as Valvoline)
Shell Rotella 15W40
Mobil 15W50 (you could do the same, but the expense is unnecessary)
Autozone 10W40
and of course the Harley stuff (which is just 10W40 motor oil with not much of an additive pack).
I like Mobil 1 75W90 in the tranny. Amsoil works great for many here as well, and my friend really likes it (he only changes it every 20K or so).
I once ran some dino Valvoline 80W90 in my tranny and found a little fuzz on the metal drain plug after about 2500 miles... but never any fuzz with the Mobil 1. I think the Mobil 1 held viscosity better than the Valvoline plain dino 80W90 did (judging only by appearance on the drain out)... But even the dino oil worked fine, and the bike shifted about as well as it did on the HD product I had used once before.
In short, the primary is the least particular part of the system as to oil. Some folks even use transmission fluid (ATF) with good results.
Next is the engine, I would say. You simply need an oil that won't shear down to water (but shearing to a 40 weight has never hurt my engine, according to UOA's).
Then the most critical choice would be (in my opinion) the transmission oil, which even HD finally is half-conceding needs to be more than Syn3 (most dealerships are persuading folks toward other products for the tranny). Get a robust oil that will hold its viscosity, which will mean a good synthetic. Mobil 1 or Amsoil either one will work.
Lastly... since you're running a twin cam, check this UOA we did on my friend's 2003 Softail:
http://bobistheoilguy.com/forums/ubbthre...rue#Post1214567
Dan