Neither produce more or less vapor. there is a balance between power, ohms, and type of coils you use. I use everything from 32 gauge to 26 gauge. the lower the number, the thicker the wire. The thicker wires have more surface to wick contact area. So... here's a brief summary of my findings.
for single coil.... 32 gauge wrapped at 1.8 ohms is a fairly small coil. However, when test firing at 5 volts, it heats up in less than a second. Thus, it produces more heat in a small area.
28 gauge is thicker. If I wrap it at 1.8 ohms as well, the coil is about a wrap or two larger. When test firing it at 5 volts, it takes a bit longer to heat up to the same as the 32 gauge.
a 24 gauge wire is rather thick. IT holds it's shape easier. IF wrapped at 1.8 ohms, it is well over twice the size of the 32 gauge. However, firing that much metal at 5 volts, it takes over a second to heat up, and it doesn't get as hot as the 32 gauge. It doesn't produce much vapor at all.
That being said... if you have a lower gauge wire, you can run it at a higher voltage and it will heat up as fast as the 32 gauge wire. I mainly use a mechanical mod with the lower gauges, and Variable voltage with the higher gauge. I have some single coil high gauge setups that produce quite a bit of vapor, but not as much as my dual coil sub-ohmed lower gauge wire.
so, your build and PV matters just as much, or more than the type of wire you're using.
