Easy stuff.

Set your max amperage at about 1 amp per thou... So for 3/32 inch stainless that would be about 95 amps.

Thorium, Cerium, or Lanthanum electrode sharpened to a point. If you dip your electrode stop right away and redress it.

For groove welds or buildup you will want the largest cup you have. Keep the stickout less than the dia. of your cup.

For Fillets, a slightly smaller cup may increase your ability to see the puddle. The geometry of fillets naturally hold your argon coverage.

Run a Max of 25 cfh for your large gas lens and as low as 10 cfh for your smaller dia cups.

Now for your exclusive synchrowave 250 tip for the day:
Synchrowave 250's made up to the mid 1990s require the balence control to be set in the 2-3 position (its highlighted) for best DC- Low amperage performance... This is a slight design glitch. If the balence is set toward Max pen the welder will have less fine amperage control through the foot pedal. It may appear wierd for an AC control to affect DC performance but the advice is sound :)