I am presuming you have moved the steering wheel forward as far as possible?
Am also experimenting with seat position so it is useful to know the limitations on adjustment.
Adjusted the seat yesterday for the first time since buying the car. Seat was a bit too far forward and my left knee was almost touching the centre console. Also with the sun visor slightly lowered (fully down was obscuring forward view) I kept head-butting the visor when going over road humps too fast or sudden braking (due to lots of suicidal pedestrians and cyclists around our way since the introduction of the new Highway Code!). I quite like the high seat position but felt it had dropped since adjustment - now I know why so will have to get used the lower position.
With our cars we are fortunate that although there is about three inches height difference between my Wife and myself, we do not need to adjust the seat position as it suits us both. My height is in my legs, whereas my Wife's is in her body so I know when she has been out in one of the cars as the rear view mirror needs readjusting as I can only see my chest in it.