i use the HS1850 for most of my winging. Would purchasing an HA1180 give me noticeably 'more' (low end, glide, etc) than the HS1850? Or less? Or just overlapping?

The new HA needs only a little more than half of the area compared to the HS. For example, the HA680 has almost the same lower end as the HS1250 (within a knot), and the HA880 is similar to the HS1550 with respect to lift and low end. There seem to be many who use the HAs shimmed to reduce lift, which also means the size difference is/can be smaller.
The HAs have more glide than the HS. The 1180 would likely give you more lift and low end than the 1850; perhaps more than you wish for, and you'd end up using a couple of shims. For similar lift, you may want to look at the 1080, or perhaps even the 980.