Honest answer, the wire you have isn't suited to high wattage builds. You don't have what you need to get the results you're after. I'd venture to guess that the upper limit for the 28g kanthal in single-coil configuration would be around 70 watts, but even then, it's tricky. I say don't bother with the nicrome. It will overheat.
It'll be extremely difficult to pull what you're asking for off with a single. 28g just heats up too fast and there's not enough surface area for the heat to disperse across. It'll be a hot, hot vape with lots of dry hits and you won't get clouds. 28g singles simply are not meant for super-high-wattage use.
If you're really hellbent on doing a single, then do a triple-parallel 28g with the kanthal. What I mean when I say that, is wrap one parallel coil with three strands. 2-2.5mm diameter should be fine. Keep the resistance between .4 and .6. That should be enough. Alternatively, you could also do a parallel twisted, or a triple-twisted. I would advise you to start at no more than 60w and work your way up. The reason you are probably getting dry hits is because you are running too much power to a small coil. There's really no easy way around that with 28g.
I think that's about the best you could easily do with singles. What's your beef with duals, anyway? Duals are much better for vaping at high wattages. When done right, they double your surface area without overheating, which gives you much more vapor at no sacrifice to flavor.
I seriously advise to you try a parallel dual 28g setup. Somewhere between .22 and .4 will yield fantastic results at anywhere from 70w to 90w. It'll get you what you're looking for.
Also, if only one leg is getting hot, then that leg isn't making a solid connection. Make sure it's snug, but not broken. If you don't, it will guarantee hot spots and dry hits. It's not as minor as you make it out to be. It can ruin your vape.
For wicking, you want the cotton to be as fluffy as possible to ensure full contact across the inner surface of the coil, but less is more. When you're feeding the cotton through the coil, you shouldn't have to tug it much at all. It should slide through easily... ...just a minimal amount of resistance to it. Lengthwise, leave only enough to touch the deck.
In the future, if you really wanna see what high-powered vaping all about, get some 26g or 24g kanthal. Those will work well for single parallels or standard duals. If you want a really kickin single that's easy, then go for the 22g.
Good luck on the chase! You've really got your work cut out for you.
