I don't know if you have looked at my 66 dart thread , But after using one of the "good " expensive $35-50 Blair cutters and waiting forever on the tips to be shipped to me,after about 50 or so cuts(yes I used lubricating oil to help cutting and heat). I swapped over to the dreaded harbor freight junk. I did use 4 bits and some trans fluid as cutting oil plus both sides of the bits taking my car apart. but in harbor freights defense they cost about $7.99 and I still can use the last one. the others need new cutters and 1 needs a spring loaded tip so it was easier to just get another one.
I hit the metal with a flap disk and center punched each spot-weld to keep both the Blair and the HF tools in the center, I did approx 500+ spot welds(I quit counting after doing the inner and outer cowl,apillars and drivers inner fender.) from front inner fenders all the way back to the rear tail panel. I think the only panels I didn't use the cutters on was the passengers inner fender,trunk lid and the radiator core support. so IMO if your only going to cut a couple hundred or so I'd go with the harbor freight. Of course the Blair cutters did come in a week after I got 90% of the car apart.