Agree with Bondo—-never seen an offset base.
if you only need an inch or so more clearance, you could make a “plate” of starboard the size of your seat base and screw it into the seat bottom and then attach the pedestal to the starboard plate an inch or so further toward the front edge of the seat. That would move the seat back and give you more clearance. You don't want to move it too far back so you don't put too much stress on the seat/base but an inch or so is usually fine. This does raise the seat height the thickness of the starboard.
I’ve done this a couple of times over the years.
If you need more clearance, the other option is to move the pedestal base back as Bondo suggests. When I’ve done this, I’ve put stainless screws into the “old” holes in the floor to help keep water out and make it look a little better.