Jchiha, Im sure youll get helpful advice from others with that combo, but it really comes down to what sort of beans youre grinding, how old they are, and other considerations such as humidity come into it too.
Why not experiment? -- Set your grinder, throw in a few grams of beans, and see how they come out. They should be almost fluffy and slightly clumping.
Dose into the basket, tamp (with your new tamper) and you should get the 30 ml or 60 ml extraction in around 25 seconds.
If the coffee gushes out in a fraction of that time --too coarse, set to a finer grind.
If it takes forever, too fine.
In either case, make sure your dosing and tamping is consistent.