One thing that will probably help is getting more wick between the inner ends of the coils. You can bridge it like you have, but make sure you take some tweezers and push that bridge all the way down to the deck so that your wick essentially forms an "M" shape. A straight bridge just creates a bottleneck on the middle sides of the coil. They're already heating each other faster on those sides, so not having as much juice flow on those ends probably isn't helping.
I think the real problem here is that those coils are too bulky and the ID is too small. There's too much mass for them to heat up properly and not enough juice to go around. With quads, there's no need to go up to 24g. The mass and surface area will already be way up there with lower guages. I think ej had it right from the get-go, try 26g. You want something that's gonna cool more readily even with the reduced airflow and chamber space.
I was digging though my repository when I found my last quad build. Can't remember the specifics aside from the wire being 26g kanthal, but in my TM, I do remember it being a warm, very smooth, high-vapor, high-flavor vape. I'd wager to guess that the ID was either 3mm or 1/8" (looks more like an 1/8" but I was using a 3mm jig more often back then.)
The large ID leaves lotsa space for wicking both inside of and between the coils. They don't take up too much space horizontally. The 26g still leaves you with tons of surface area, but it doesn't have that nasty habit of clinging to heat like 24g tends to when you pack too much of it into a build. Wicking demands are far lower with the coils being so narrow, which I think is crucial with quads. The narrower they are, the faster they heat up and cool down... ...which gives you better vapor production for your power while also giving you a smoother vape, as the wicking and airflow have an easier time doing their thing.
So maybe try something like that. I remember running that baby all the way up to 150w with no trouble. Killer vape. I just don't do it because its so time-consuming. Just trying to give you some ideas. I don't know why you're having trouble with your quads. It's a little weird that vapor production is a problem. If anything heat and wicking would be my primary concerns. What you did should be a very slow, very hot, harsh, BIG vape... ...assuming they're firing evenly, that is.
