Great into, thank you. RE seat heights, this is why the standard GS I tried was as comfortable as the lowered GSA. Also, very similar to the used 900XR I tried which felt more like I was sat on it and not in it.I had a 2018 1200 GS TE and swapped to a 2020 1250GS TE Exclusive.
On the 1250 the engine pulled better throughout the rev range, when I ran both bikes in I noticed the difference on the 1250 straight off the bat. The dip in the torque curve from around 4000 to 5000 rpm I had on the 1200 to get that bike through the emissions wasn't there and in the upper rev range the 1250 kept pulling to the red line where as the 1200 ran out of puff. The hill hold was better on the 1250, the release on the 1200 was clunky if I did it in auto mode especially on steeper inclines and I ended up releasing the hill hold manually on the 1200 ( The 1200 took more throttle to get the hill hold to release than the 1250 in similar circumstances) The QS was smoother on the 1250, but still not as smooth as an il4. The rest of it from memory was much the same on both bikes the ESA, Cruise control, lights are the same, some didn't like the Hayes brakes on the 1250 over the Brembos on the 1200 but I never noticed much difference. I traded in my 1250 nearly 2 years ago for an RS so I might have forgotten a few other differences. In essence in isolation you won't be disappointed with the 1200 and that looks a nice example. IIRC the lowered GSA has the same seat height as a standard GS @ 850mm, the lowered GS has a 800mm seat height with the low seat.
I think all things being equal the 1250 would be a no-brainer but at the moment the last of the 1200s appears to be a sweet spot for spec and price, and represents best bang for buck with 90% of the ride.
The lighter and perhaps more nimble GS would probably be the more suitable 98% of the time as a daily and for weekend group rides on Dorset A/B roads, but the GSA would give benefit for a couple of times a year touring with full luggage and eating up motorway miles on absolute comfort.

