The answer is pretty basic as you found:
Modern off-shore 5AR4s are crap. They will not pass enough clean DC current for the amp(s) to operate properly.
There are after-market solid-state 5AR4s which are adequate, far better than the Chinese/Russian garbage. Search for "WEBER COPPER CAP", and you will find the one with the best reputation *and* a built-in delay.
And there are delay boards (15 seconds is suggested) that may be had as well. Neither of these devices likes short-cycling, so do understand that before investing in them.
The most common mod on the Weber is to remove the cover, ventilate it, and then put it back. They get HOT!
Melrose Park, PA