I've used AMSoil in all my Harleys and wouldn't use anything else. They make a primary oil now, and I like the 75-90 severe gear in the tranny. Have used it in all my previous Harleys as well, and would highly recommend it. Really quiets the tranny down and smooths the shifting. They don't recommend it if all you ever do is make short trips, but if you like weekend rides, etc, I think you could do worse.
As far as making the switch to full synthetic, the sooner the better with a new engine is what I've always heard. I don't think I'd wait until the 10k checkup to do it, but that's just me talking. Seems to me I switched to synth at the 5k mark in one of my bikes without any hiccups.
Do some on-line research first to satisfy yourself. Heck, call or write AMS oil and get their opinion. Or call any reputable synth oil manufacturer, and ask them too.