Hi Anne, can only speak for RIB swivels but:
Passengers: Seat height increases by 23mm
Drivers: Seat height increases by 43mm with the spacers fitted so the swivel clears your handrake on the way around.
For seats fitted with up/down height adjustment (that is mainly drivers ones) you will find that you probably need to pump up the seat height to allow the seat to rotate without the grey plastic trim around the base catching on anything.
Similarly, front/back sliding depends on what height you like your seat to be at. If you typically pump the seat down low you'll find the grey trim plastic sits down onto the release lever so your cant slide the seat, you therefore need to pump up the seat before sliding front to back.
Hope that helps.
Rob.
www.kiravans.co.uk