Glad you sorted this and got a working amp. It was a really great troubleshooting thread for the startup procedure and I definitely learned a lot!
Good job, sir.
Forgive me for revisiting LBL details. I may have missed lots; I’m just catching up to this thread. Lots happened! I see my guess about the no-tubes startup not lighting up your 150W bulb echoed by smart people. But do I read right that you were measuring voltages on the LBL? Maybe not. If so, though, it makes sense they measure better on the 150… more current, less limiting. But also, recall voltages and sound on any limiter may be inaccurate — sometimes by a lot.
The difference in current calculations between the ot measurement method and the cathode resistor method is due to the cathode measurements including the the screen current. About 2ma each is about right. Personally, I think you could bias it a bit warmer (both over 60% dissipation) but if it sounds good, it is good.