Well a month ago I cut out the seat and made some tests with a seat from the new Coastrunner k1 trainer. The result wasn't good. After 25 km of paddling my butt was hurting a lot. I only managed the 25 km back again as a mate borrowed me a cushion.
I then contacted Nelo, only to be adviced against using their racing seat in the Inuk. It would take a lot of work to fit it I was told.
Luckily the swedish paddler Erik Arnstrøm had recently posted a notice on his (highly recommendable) blog on using a Plastex racing seat in a sea kayak.
Soon I had a Plastex seat and with the help of a handyman in my kayak club, I got the seat installed 8 cm above "ground".

Now for the verdict.
As for the paddling poisture I'm enthusiastic. The forward stroke definitely feels more powerful but I haven't got numbers to back that claim yet.
The center of gravity has moved up quite a bit and I lost even more contact with the boat, so it goes without saying that the boat feels a good deal less stable. That doesn't worry me though - as I consider it a fun challenge to improve my balance. Besides I spend time each week capsizing on purpose anyway.
As for sitting comfort, the Kirton seat was better. I went on a quick 20 km training paddle today and felt a tad sore in the end. Still I only had the seat for a week, so I guess it'll only be better.
Last thing - handrolling has become easier! The Inuk was always easy to handroll but now it's even more so. A couple of the other greenland maneuvers also got easier while I haven't noticed any maneuvers got harder.