Pushrod oiling/heat?

I'd call that a bingo! That is a LOT of oil running out at the pedestals instead of pressurizing the shaft, especially only at priming speed.
If your geometry is bad enough to need those shims then call B3RE yadda yadda...those regular shims usually do more harm than good. FWIW I've run those red Manicini rockers and they oiled the pushrod cups fine...
Good job catching it before something failed!
Yeah I'm glad I decided to pop the covers off today!!!