When we replaced our Oasis with a TI back in 2010 the only complaint my wife had was that the pedaling position wasn't as comfortable. She didn't like the way she sat lower in the seat and the raised position of her feet on the pedals. Moving the seat to the forward plugs improved it but she much prefered the higher seat position of the old model Oasis.
I looked into skipper seats and decided against them because we use our TI as a kayak often. I tried some foam packing but it kept slipping. I realised that in order to raise the seat we would need to get seats that had four straps and build up the seat well so that it didn't slip, but could also be easily removable.
We ended up getting a Surf to Summit GTS Expedition Seat:
and a cheaper but more versatile Sea to Summit Cruiser Kayak Beach seat:
To raise the seats I used some contour fenders that I had lying around
Encased in a very tough layered material, I thought they'd be strong enough as they are designed to fend off boats [do not insert joke here ...slaughter are you listening?] and are closed cell foam so they won't absorb water.
By cutting them at the fold I was able to get enough for two seats after I added some closed cell foam to fill the gap of the shorter sections.
By punching a small hole in the fender flap, the original Hobie seat pegs can be used to stop any sliding. Sitting them on the original Hobie seat bottom keeps the drain plugs clear and adds more height and comfort:
With four straps both seats can be fixed using existing fittings:
My wife finds both seats to be very comfortable but prefers the thicker base of the GTS Expedition.
I prefer the Cruiser seat as it has a very comfortable seat back that wraps around you well and is great for sailing the AI in kayak mode. It also can be removed and used as a stand alone beach seat:
This mod has raised the seat height about 4 1/2" for the GTS and 3 1/2" for the Cruiser seat over the original Hobie seats.
Both seats got the thumbs up after 12 days of recent testing. She finds the raised seating position much more comfortable for pedaling and of course likes the added benefit of not sitting in a puddle.
Undoing the bayonet seat pegs makes it easy to remove the fenders for use in kayak mode.