I would say 3/32" tungsten should take care of everything that machine can put out. Use 2% thoriated or lanthanated. If you lean more towards sheetmetal work you can use a 1/16 tungsten up to about 100 amps. Different grinds on the tips can extend the range of a tungsten. A needle point on 3/32" works about as well at low amp sheetmetal as a normal grind on a 1/16" As to filler, my go to rod is ER70S2 1/16" It will work for everything from sheetmetal up to about 1/8 without going too fast. If you will only weld 1/8" and thicker, you could go a little larger, but I think starting out, you tend to be a little on the slow side, and the smaller filler will be easier for you.
Long arc, short arc, heliarc and in-the-dark!