Modern Vespa

I bought an air cushion from BadAss Moto for a solo ride from Philadelphia to Richmond, VA, as non-stop as my tank would allow. It absolutely worked and I was pretty comfortable the whole way.

The problem is that it raises the seat height by an inch and a half or so. I have short legs and my GTS height is about my limit. Hard to remain stable when I had to stop abruptly.

How do you stay comfortable on long, non-stop rides?

I would like to have my seats reworked to better cushion me bum and surrounding bits. However, I'm scooter rich and cash poor. I received this recommendation from the WildGuzzi forum and he's sent them all of his bike seats. http://www.meancitycycles.com

Air Hawk seat cushions work best when they're barely inflated, so that your butt just touches the seat. You didn't say what kind of air cushion you have, but you might try adjusting the inflation if that's possible.

I use a sheepskin pad on my GTS (Alaska Buttpad). Substantially improves comfort for longer distance riding and makes little difference in apparent seat height (less than 1/2" I'd say).

I usually peel and reshape my seats with a kitchen knife and angle grinder. The vinyl cover adapts to subtle recontouring while restapling.. Local upholstery shops can do this in an hour or two. The shape is the main thing to consider, as it should fit your buns.
It's a common task for upholstery shops to lower seats. My friend Peter had his done for $90 by a shop that does hotrod interiors and boats.

Thanks. Going to try that. I had it fully inflated. I mentioned that I had a BadAss Moto cushion.

I'm sure that would work, but I'm reluctant to modify the OEM stuff.

Buy an extra seat, maybe second hand, and have that used for modification.
You could mount the original seat for every day short trips, and the modified one for the long journeys when comfort is more important than looks.

That's a good idea for one I already have, From my '07 GTS.

I understand that concern. Used seats might be an option or the custom makers like Sargent who make lowered seats. My mods are because I'm too dang tall.

Do you ride by yourself rather than 2-up? I switched out my stock seat for the Vespa solo gel seat. It is a bit lower than the stock seat and the gel layer adds to riding comfort. It is not so expensive as custom seats from some aftermarket makers. I added a sheepskin pad to this and the combo has served me well on my GTS. (the stock seat is still in the garage and can be switched back in no more than 10 minutes, so i haven't really given up anything)

https://scooterpartsco.com/vespa/gts-300/gts-300-seats/low-profile-gel-solo-seat-for-vespa-gts-with-abs?zenid=bfd1a3d66c348a4b5bd45afca1dc9ea8

As mentioned above, the cushion should be inflated to allow you to almost bottom out. The air chambers are interconnected and it should feel squishy as you move around on it.

I had really good luck with a barely inflated Air Hawk under a quilted seat cover from Cheeky Seats. It was super plush and I could ride for 8+ hours pretty comfortably.