Just built a WW shop about 50' (cable length) from my service panel.
What gauge wire should I be using? 4-4-4-6? If so, should I pull
them all individually? Or buy the premade 4-4-4-6? What size
conduit? 1.25"?

Shop is 16X20, may consider a/c eventually too. Aside from that, I
have all the other goodies, Table Saw, dust collector, Compressors,
I'll need a ton of lighting, etc...

Would I ever really exceed 70 amps? Could I maybe get away with
6-6-6-6?

Thoughts? Experience?

Thanks!

Elmar