I'm pursuing a couple of options on a 2006 2305 which has a pretty small operator area. One is a trac seat.com or an equivalent from all parts.com A-W222yl or A-T333Y. They all have a 7 x13 inch base that is drill able to line up with your frame bolts. The seats have five adjustments of base angle. They operate with adjustable spring, scissor action. Trac seats rates theirs to 275. All parts has 265 and 300 pound ratings these are only about $100 with shipping. No operator presence switch and you have to figure out seat belt mounting. I really wanted the Big Boy seat but it wouldn't fit and was $329. Amazon sells all of the above. A Cadillac seat is the Milsco V5300 in black for about $400 and then you have to figure out rails and mounting +or - $200. I am pursuing placing my existing seat on a JD AM 134254 scissor suspension. This kit is $185-204 and seems to include rails and lots of option. An Internet search will help with pictures.
I found a salvaged one and am working it out. It is spring driven scissor action and appears to be fairly standard JD in 500s, 700s, and the 1025R. Should you go that way and you find the springs too light duty visit Ken's Bolt On Hooks for an upgraded spring set at $30. Also Tractor Time With Tim on You Tube shows him swapping out springs on the 1025R. Internet search: 2305 suspension seat and New Seat 2520 on MY Tractor Forum.com. Standard Internet searches and You Tube produce good info. I can't get anything out of a tractor by net search. There is a true air seat available with mounting rail modifications $800+?
I bought a trac seat through Amazon with a credit card app gift card delivered for $48.99. I paid $20 for new seat biscuits the other day. I stumbled on the salvaged JD suspension scissors and found My Tractor Forum photos to scab it onto my rails. I'm prepared to spend another $100 on that option. I have a rider I can put the extra one on. I think the geometry will decide for me. Anything has to be better than the rubber biscuits.