Just for future reference, I like to put at least 2 coats of epoxy under the 2K for a couple reasons. First is the extra corrosion protection it provides, and second is as you are blocking the 2K you will inevitably go through to the epoxy in places. If there is only 1 coat metal will appear real quick. With 2 or more coats, you have a little more room for error. If you do hit metal you must spray epoxy over that spot anyway, ,then wait overnight, so you're not saving any time. High build 2K has quite a bit of wave to it, and starting with 320 will not get it out (ask me how I know). Start with 180 minimum, even though I have been starting lately with 120 with good results. If I were you, I would go ahead and sand it lightly with 180 then spray 2 more coats of epoxy tomorrow, with an hour in between. Wait and spray your 2K the next day. I think you will be ahead in the long run.