I would go longer, if you want a bit less SA go narrower! That should allow you both downwind and some reaching ability.
Reality is, if trying to go downwind, make it as big as possible both length and width. Especially since you are not racing nor trying to fit a given size rule.
To get a bit better straight down wind performance, once you are used to it, get an actual spin pole, attach it to the tack, some lines
attached to the pole, you can pul the tack to the opposite side of the main, and get some better performance downwind. We've been ding that racing, works pretty well. Allows us to get into the 160-170 range vs only 140 without.
I've also seen a few folks try to wing on wing and AS like a jib
, but with out a pole on the clew, that makes for a hard way to work, as the AS will collapse, or the main will gybe if you are not being really careful. I actually find a 155 on a whisker pole to be better than winging an AS to a degree.
I would also look at the CS/north AS if it is the correct sizeing. BUT, there are a few places that are doing some 30% off if you order by 9-15 to 30 and wait until march for delivery. So if you are a northern east coaster, out of the water from Oct to march/april.......that could be a better deal yet! altho if you sail year around as I do......maybe not. THen again, the winds are typically a bit stronger in the winter........but we still get a lot of calm days here in the salish sea......just a few less in the winter than summer.