I have never used that exact machine but amps are amps. Here are some general amp starting points for your practice.
First rule is that the better the material transfers heat the more amps you will require to weld.
Aluminum requires the highest amperage settings
Mild steel is a good conductor of heat so .125 wall might like 130 amps depending on your skill. the higher the faster you need to be.
Chromemoly is not as good a heat transfer as mild steel and will need a lower amp setting than mild steel. I weld .083 near 50 to 60 amps at most.
I also use .060 filler wire crown 8.
When welding moly do not over heat it ever if you can avoid it. Be sure to clean it up with a sanding disk or flapper wheel or however you prefer to both inside and out. Do not try to drop the weld in like you do with mild steel. The moly will weld inside with little heat requirement due to its ability to store heat and not transfer it .
Stainless steel welds very close to the same amp setting as chrome moly the same dimension. If you have 316L stainless experience, carpenter 20 or 308 stainless you would not need to change the machine between them. Hastalloy and Incalloy require even less amperage.
The best thing to do as a beginner is clean every thing well and brush your weld before it cools and as it cools to let you restart easily with out contamination that you will be able to burn out later when you get better at the skill. kevlar gloves are great I think because you can feel the rod in your hand better and get better rod control.
Glad you are stimulating our economy with your new purchase. I have welded process pipe in Dow chemical for years to support my horsepower habit and build chassis cars for enjoyment. Tig is king, once you get it you can weld anything. Good luck
Bruce