Which Williams wheel?
 

Williams System 19 or System 30 for a recreational rider? And why?

Would these be an improvement from my Shimano RS-10s?

It is confusing when looking at wheels, and I'm not sure how much diffence a 100 grams would make or the aero rim would make when comparing the two Williams wheels.

I ride mostly by myself, but am starting to do some group rides and some rides with a couple friends. Typical distance is 15 to 40 miles. Terrain has some flats and some small hills.

Thanks.

Go with the wheelset that looks best. Seriously, at this stage you wouldn't be able to see a difference in performance.