Scrap the 2000 for primer work it won't give you anywhere near the key you need for adhesion, you want to be around 400-600, 600 for your final prep before basecoat. Or if you can apply your primer good enough, a few coats with a quick rub with a scotchbrite pad between would be ideal.
Yeah just key your etch coat up, either with a scotchbrite or equivalent, then hit it with a decent quality primer with a quick rub down in between. Personally I give 2-3 coats of primer depended on the build required, but I only key up between coats, I do my final shaping and dressing in the last coat when you gave a decent depth of primer to go at, otherwise you risk rubbing through the lot!