Haha, i've clayed numerous times already and it still takes me about 1 1/2 hour to clay an SUV, Probably because i also form and shape the clay those get those hard to reach crevices.

As for the Showtime Instant Detailer, i don't think it could offer protection though, sad to say that, but in some ways it might help in cleaning your car again, i had a similar scenario one time when i was claying but didn't have enough time to get to step 1, so what i did was leave the car, get back to it the next day, used California Duster to remove dusts and boy was i impressed, the dusts just seems to glide off, i think the lubricating properties of the detailer was still there, i washed it again the next day and the dusts seem to just foat off even with just water, dried the car then applied a wax and sealant combo.

i think this would be your safest best, to wash it first and then wax it after.