My ST1300 was the 2008 model and I had a fitted lambs wool seat cover. I found it very comfortable for long days in the saddle. I also have an Airhawk for the VStrom and one for the Himalayan.
I found the lambs wool better than the Airhawk for the ST in terms of comfort. I have a Sit & Fly mesh cover for the Vstrom which is fine for local rides but if more that say 300km then the Airhawk gets thrown on. The Himalayans seat feels like it's made of teak with a film of foam wrapped over it so there is an Airhawk on it permanently.
My 2 cents - get the fitted lambs wool cover ($315 + postage I'm guessing). An Airhawk at $170ish (& $160 for pillion - if you get both it's more expensive than the lambs wool) is ok but not as good as lambswool (IMHO). I'm told the Russell Day Long seat is the very best - but I've better things to spend my $'s on, given the lambswool suited me fine. I don't reckon you'd get any change out of $1,000.00 + postage times 2 and that's just for the riders seat.
https://www.goodwool.com.au/product/custom-made-two-piece-seat-cover/Model for the Airhawk - not sure they look to have changed the designs. I'd say both are the touring seat. and they look like they're the medium cruiser but a bit smaller. I'd say with the current models the Airhawk RL would be the best for the ST
