Figure I should post up here since I have a similar new rebuild. Engnbldr Street RV head, 261c and the DT header. Machinist has built plenty of 22REs and said all he needed to do to my rockers was polish them a bit. Did not need to deck the block. Valve lash set to 007/009.
Anyway, I could not be happier with how this motor runs. No issues with idle and starts with a blip of the key cold or hot. It has the quietest idle out of any 22RE I have owned (10 or so at this point) and definitely pulls harder than any of them. I have about 100 miles on it so far. And it does not seem to getting noisier. Like most of us I am super familiar with the valve chatter and this just does not do it for some reason.
I have never had a fresh rebuild though to compare it to. My last truck came to me with a rebuild with 30k on it, stock head, DT and the Comp Cams 252S. My butt dyno says it did not pull as hard as this new motor, although that was 33s/4.88 and my current ride is 35s/5.29. I could not get that previous motor to have a quiet valvetrain.
I'm in CO, so I will be doing emissions on a dyno. I will report back here with how that goes. They can't really test for lean but if I have high NOx that would be a sign.
I haven't read through this whole thread but are you sure your timing mark on the damper is correct? I had that slip on an old motor once and ended up timed 10 degrees ATDC when I thought I was spot on. Caused all sorts of misses and SUPER hot exhaust.
Long story short, unless that 261 is defective I doubt changing cams is going to fix your issues.