Well I hope that you have figured out all of your problems before attempting a choke mod.
The choke (you have?) is one of the chokes designed for a 100 watt Marshall. However, there is a different choke for a JCM2000 and it is only 3 Henries at 100 mA. See:
Mercury Magnetics
Go to bottom of page, 100 watt chokes. I think the 3 Henries is the one you use in the TSL, but you can always contact Mercury Magnetics and ask one of their techs. The wrong choke can spell big trouble.
Marty