On my 2015 Mojo, I installed this unit

https://www.iboats.com/shop/garelick...ze=12+to+17%22

It has a pin lock to set the seat height, then the knob tightens against it to firm it up. I still have some wobble but it is from the seat to the riser, not the riser itself. I keep the seat a little lose so it will swivel and then deal with the wobble. Not sure how the new Mojo seat is, but i know the higher end boat you have to release a lever to get it to swivel and the seat stays firm.