Here is the base that I ordered:
You remove the seat from its base and insert this between base and seat. Four bolts are included. Raises seat about 3/4". Will operate without any further modification. Easier to swivel if you open the door, but will work without opening the door.
It is easy to install. Best with two people just to handle the weight of the seat more easily.
On the 2300 I did only the passenger seat, as the driver seat would be partially blocked by the dinette. Have had this for 2 years and love it.
2012 Forest River Sunseeker 2300 Chevy