From research, to my understanding I use a 20awg(about) wire, two insulated alligator clips one clamped to the chassis and the other at pin #1 of V1. A wire a resistor in series so it drains more safely. Correct?
Agile AL3000
Douglas WRL90
J&D Strat
Squier Tele
Sammick TR2
Douglas Draco
Peavey JSX
Bugera V5
Correct. You could use higher than 20 AWG and be fine, but using 20 AWG is good practice.

One alligator clip on pin 1 (or 6) the other on ground (chassis). You do not need to put a resistor on the alligator clip or anything. The voltage will bleed from the HV caps through the plate resistors to the path you created to ground.

FYI plate resistors go from the HV supply to the plate (pin 1 and 6 on 12A_7 type tubes).