"i think i will do some kind of cooling mod as well. i can't make more than 50 welds before it hits it's shut off temperature. and regular cooling takes more time than i need to cut the next nickle strip in shape."
In the picture if those are your probe cables they look like "audio type copper clad" wires, I had similar and they didnt transmit the full amperage to the tabs. To compensate you have to increase the power of the welder which is making it overheat and probably making the wires hot.
Using the 6 gauge pure copper welding cables for the probes will let you reduce the power output and probably you wont need a cooling fan. Since switching to pure copper wire I can work nonstop, no fan required, wires barely get warm. i was able to do an 80 cell pack in one sitting, and could have kept going if I needed to.
I read a comment that thicker gauge wire on the probes will damage the fets, if anything it might be beneficial since you will be using lower power rating to get the same results. With high amps, thicker gauge pure copper wire is always better, only drawback is that its more expensive going that way.