I'm actually pondering that question now. I have drained the oil again, and removed the chain tensioner and oil pump from the 1-3 side. My thought is that if I can loosen the four bolts holding the exhaust timing gears together
I may be able to advance the cam timing enough to get the valves out of the way so that I can get the engine to TDC. If I can do that, I can lock down the cams in the right place and retighten those bolts, and get the timing correct without removing the engine. I haven't had the chance to try it yet, but that's my current plan. I figure that if it fails, I'm no worse off.