That is a very nice upgrade andy77 --youve eliminated some intermediate steps in machinery.
In so far as as the variables -- one step at a time is best. Change one thing, get that right, and move on to the next variable. Otherwise you wont know which change worked.
First of all, assuming you are using fresh beans freshly-ground, get the dosing right.
DOSE: Weigh out, say 18 grams of beans and grind.
TAMP: Aim for a 15 kg tamp (put the portafilter on a bathroom scale and tamp. Youll soon get the hang of what 15 kg feels like without the scales).
How long did it take for a 60 ml pour?
GRIND: If it took more than 25-30 seconds, grind a little coarser. If it gushed out well before then, grind finer, all the while keeping the tamp a consistent 15 kg.
That should give you some consistency and good coffee.