I looked up Z-Foil and they describe it as something in their Bulk Metal Foil resistor line.
Not tin to dampen out vibrations?
Something heavier?
These metal film resistors (see below) are going to be better than what I have, just have to double check the tolerance.
https://www.mouser.com/ProductDetail/Vishay-Dale/CPF211R000JKB14?qs=r9s7qWT5I1UpUeXAc0r4NQ==
This is what a friend wrote to me a few years ago regarding my two SE100's........Quote
if you decide for carbon comp or metal film it should be carbon comp or metal film on all tube board and both amps......
You have to solder both sides to be sure.
Lift the resistors about 3mm of the board (use a shim for consistent job) before soldering.
This way the air circulates around the resistor cooling it better and promoting board longevity.
End Quote.