well without knowing the max discharge rating of the cell, your only way to know if it is being pushed beyond its limits is if it heats up a bunch during discharge. but since the entire tm2 unit heats up I doubt a person could distinguish. if it was me i'd spend the $4 on a p30b from a trusted supplier (the trusted supplier part is a big deal). Or better yet if you can swing it get 4 of them and be set for years.
My usual source is liionwholesale.com, but imrbatteries.com is selling the p30b for $4 each:
Molicel P30B 18650 3000mAh 30A Battery – High-Power, Fast-Charging Solution for Premium Applications The Molicel P30B 18650 3000mAh 30A Battery (INR-18650-P30B) is at the forefront of ultra-high-power cells, offering an unparalleled power-to-energy ratio within the 18650 format. Featuring a...
imrbatteries.com
Also, please note that if you have unwrapped the cell, it is no longer safe to use until you wrap it again. short circuits and all that. If you plan to rewrap it save the little black plastic disk that came off the positive end when you unwrapped it. its an insulator that goes on the positive side between the cell and the wrap. If you lose it you would want new ones of those too.