I do and did color sand the work between coats but did not wet sand the last coat. I could do so but do not intend to do so. I am quite happy with my less than perfect results. Keep in mind, as I mentioned earlier, vintage road bikes were, particularly the entry level steeds, were not mechanical art. In fact they were hastily made, painted and assembled. This is the sort of cosmetic quality one can, often times, expect from a lower tiered vintage road bike...
So, the last coat goes on as carefully as I can apply it. If good enough, then I am done. If not, sand and apply another coat.
I did not thin the paint. Rustoleum recommends against it and, to be honest, there was no need to thin the paint. It goes on well and flows to a smooth shiny surface...
I still have some clean up to do and possibly a wee spot of touch up. I have, pretty much, done my last bicycle paint job. Eyes are dim and hands shake too much for fine work. But ya never know. I still have Torpado's top dog, from the same era to restore, and I am gonna give it a shot next Spring - early sixties Torpado Professional...