Compared with my original seats, the revised design is like comparing seats for a truck and seats for a Rally car.
The base is much lower, and angled back, with foam lumbar supports - I integrated the components of the IVIBE unit inside the foam, to acheive a better design.
The front of the seat is 45 cm high, and the rear around 35cm - I made a crude adjustment mechanism for the back, but the height is not adjustable.
We don't have a working sewing machine at present, so the headrest and top seat cover are made of glued leathercloth - at some remote stage in the future, I will redo the covers.
The rollers worked OK, but still.. On a trip to my local DIY store, I saw the tracks and rollers used to fit sliding wardrobe doors.
The advantage is high quality bearings, well designed tracks and rollers, and very low friction. Another advantage is the little stops, which can be used to fix the seat in your favourite seating position.
They work so well, I had to add a heavy duty stop at the back of the floor, to stop me propelling myself out!
There are various types available, for different weight doors. I used 4 50Kg rollers per seat, and 1 pack of 1.5m track - make sure you get the ones that fit on the floor, not the top ones, used for hanging doors.
The rollers are fixed to wooden battens fixed under the seat, at the correct angle to give full sideways travel, and let into the MDF of the base to reduce height.
Not cheap (certainly not as cheap as roller skates!), but work very well.
Here's a close up of one of the roller wheels: