Aluminium is at its most susceptible to crack when it’s hot. This is when it’s most brittle. The coupon size won’t be helping and neither will the speed. Those look like they want a chunk of travel added. The reason you probably don’t like those settings is you probably travel slower than they are set up for.
For the settings it was giving me your GSXR would not have had enough accel I was going like the clappers with them as I could see it instantly drooping the surface of the Alu.
It was an eye opener for me regarding currents for Mig v penetration. I expected it to be much higher than it actually was.