Should I use it on a very massive,extremely abundant arti oceanic with large moons that I own, or invade a small, very rich arti with a stealth screen, or invade a small, extremely rich arti icy with a zolazin analyzer.

Invade a small, bad planet and then use the hyperterraformer on that.

You can install an assimilation locus on it because its newly invaded. Its best to invade an icy, volcanic or ocean in order to put a planet specific art on it right before you use the HTF

S/ER Icy with Z. Analyser

It changes any planet to a Massive Exotic 13x. So don't use it on a planet that is bigger than massive.

Take the small icy, if can throw on a locus and a permafrost on it as well before tranforming.

If you are artifact poor, you can place 2 Adaptive Spires before the transformation too. That way you get +4 to arts instead of +2 to all, and you can go back later and remove and replace them later if you need the other resource again.

steal a good planet, and use the hyper terraformer to piss the guy off

This was sarcasm, I think. Do what Littlefluffy suggests instead.