*SG: well if i were you i would apply 2 coats of 915 instead, i've had certain experiences with Top Coat not really playing quite well with certain waxes, i've tried Top Coat with 476 hoping to add shine and it did, but on 915 it actually made the paint a little dull where i liked the 915 look better, it also doesn't play well with p21s and souveran. but to answer your question Top Coat should be on top.