i have to say i am the same, normally fish on top of a another bait as a visual thing but thats not to say it wouldn't work how you describe, popped up over some maize maybe.
on one of the france trips last year i fished with just maize on the hair 3-4 bits with the full intension of swapping over to a popped up bit of corn over a couple of bait spoons full of maize, the grass carp went mad on the maize and ended up not trying it.
but why wouldn't it work ?