Carpro iron-x works really well but does it ever stink. Not sure why they bother advertising scents when they all smell awful
I've got a bottle of carpro eraser which is a good out of the box paint prep. IPA mix is probably the way to go as a more cost effect alternative.
I have been meaning to try optimum ferrex but haven't got around to picking up a bottle. You can use Optimums clay towel in conjunction with ferrex which also acts as a clay lube. I watched a friend do it who's a opti-coat installer and it saves a bunch of time during the decontamination step as you combine chemical and physical decontamination together.