My own thought process goes like this. In parts of the amp where the signal doesn’t flow, the power supply for instance, I want it as quiet as possible. I generally use carbon film or metal film there. I also use a fairly high wattage where possible to prevent damage down the line.
Then I think about where there is potential danger for surges and stuff and make sure those resistors have enough wattage. To me, the 100K resistors fall into this camp. I like those to be at least 1W and I usually go carbon film there.
The resistors where the signal will flow have the most impact on the sound and might add some warmth and “color”. But also noise. That is the trade off. The tone stack might benefit from carbon comp. Personally, i wouldn’t use a carbon comp on the 68K at the front as any noise that is introduced there will then be amplified along with the signal.
Experimentation is the key but be cautious as to the wattage. On the Two Stroke, it is pretty forgiving, but what you can get away with on a Two Stroke you might not be able to get away with on other builds 