If you don't like the twins, than you will have to find something that fits that is similar to the Jets. You may like the Mares Quattros..They are a paddle fin, rather stiff, but not jets. I have a similar issue diving dry vs. wet. My dry fins were too big for diving wet, and when I tried to use them I was COMPLETELY uncomfortable in oversized fins.. it in a word it SUXS.
I purchased another set of fins so now I have two sizes one for wet, and one for dry.
Your foot nees to fit snugly inside the fins, or they just feel wrong. You may like your Jets, but I'm guessing that foam, or some other such band-aide to attempt to make a too large fin work with a smaller boot is just going to lead to discomfort.
I would also suggest NOT diving Rockboots wet unless you just love the feel of rockboots for whatever odd reason. I think you will find that they are cumbersome and unnecessary in most warm water diving.
Good Luck,