Adjusting boat trim

I was wondering what options there are to adjust the seating position in a ski (I have a Fenn Spark).
Also whether people find they change their seating position in their boat from flatwater to Ocean.
Thanks.

You can adjust your seating position forward with a pad behind you, found this made my Stellar SEL run better, however made my Swordfish run worse.

Same as Greg. Pads at the back of the seat help with posture and overall paddling and gliding performance on my old SEI and current SR. Tried the same on my Swordfish and ripped it out after three sessions. Just did not feel right.

Mick