.45 is super-low for a single coil. You could go well over an ohm and it would still charge like a bank you've overdrawn from.
I like dual claptons a lot. The wicking keeps up better for a smoother vape and the extra wire helps displace all of the excess heat. I know some people like to do fused claptons and other more compelx builds, but I find that anything parallel is too much for me in series. There's no need to double your current when you're already working with 8 odd volts. It's better to keep the resistance up. That being said, a single fused clapton or some sort of staged coil is probably doable and damned good if you like singles.
I like a dual 9-10 wrap, 3mm dual 40g/24g kanthal clapton for the spacious, airflow monsters. It ohms out to around .5. That, for me is a very smooth, but powerful, billowing vape with plenty of flavor.
For something spacious with moderate airflow... ...say a Wotofo Lush with a 510 tip or the Sapor, I will usually opt for a 2.5mm-3mm dual 38/26 at around .65 ohms. It's a tad throatier, but the density is better and the vapor production is more manageable.
For my shorties like the Freakshow Mini and the Snubnose, I go for .8ish dual 38/28's. That's still quite warm and the vapor production is moderate, but the flavor is bangin and the texture is very taffy-like.
Straight dual 26's or 28's between .6-1.0 can be pretty nice. Dual 28's can actually hit pretty hard at above an ohm. Dual 24's can be pretty smooth for how aggressive they are on a Twisted Messes. I remember doing something like 10-11 wraps @ 3mm and liking that quite a lot. I tried going higher and doing something like 13 wraps, but at that point the coils were too big and the wicking wasn't there, even though they were still kicking up a lot of heat and vapor.
I've been meaning to try quad 28's. Seems like it'd be doable without being too huge to fit at a reasonable resistance. I don't do quads often, but I find that they do wick better than duals for high-powered builds. You get four sets of wicks feeding your surface area instead of two. Quads suck for low-power, but a series box should have the power to get em going and the extra wicking would probably help tame them a bit.