New to CNC

[JAZZCNC]

I plan on using Acrylic for the pieces, though I'm also toying with casting Pewter pieces and then engraving the numbers on them - would a 3020T cut soft white metal pewter ?

Good choice for a learning machine but don't expect the world from it. My advice for these machines is not to waste money trying to make it better, instead work it to death and make it earn money for the next one.!

Yes, it will do it if you take light cuts and use the correct tool with correct feeds n speeds, etc. However, if the spindle is one of the cheaper models then the runout and power could make it a challenge.
Be prepared to snap a few cutters at first and strongly suggest you cast some extra pieces to practice on first. Go's without saying you should test the code on something soft but dense that will hold an edge first. Model foam or clay is good for this, even acrylic. I suggest you use Cast acrylic as well because it machines so much nicer than the other stuff.

Can't help with advising on sketch not used it enough for drawing and never for spitting out code..!