i myself have a hard time getting in-and out-and for what i heard, everybody else.
from the beginning, i found myself squeezing in and wondering if could be a way to do so with minimum effort.
tried everything, and eventually found a way that makes life less difficult. this is what i do:
1st, got a soft cushion covered with fabric, about 1 inch thick.
2nd, i approach twisting myself to the left, then sitting.
once sitting, i twist myself to the right, and at the same time bend my legs and squeeze them under the dash panel.
the cushion helps me to slide and rotate.
exiting is done 1st rotating and unfolding my legs at the same time.
once touching the ground, i stand up (not without some effort, i would say).
now, how you do?
anybody?

 

That works. You want to avoid sliding on the seat bolsters because it breaks them down. Plop you butt in the middle of the seat, then swivel as you said. I had the same problem with my 1974 Triumph TR6. It is a two-seat SPORTS CAR.

 

the devil is in the details
the good thing is that, as i slide and rotate ON the cushion, not the seat, there is no break down of the seat bolsters. the cushion does not rotate. less friction than plopping in the middle of the seat, then swivel.

 

I use a 2x2 section of garbage bag.

 

whatever works...

 

Years ago when my dad had back surgery and subsequently had difficulty getting in an out of his car one of the recommendations by the physical therapist was to use a plastic bag to assist with the sliding/rotating movement into the seat. Worked like a charm.

 

it does work.
the thing is...plastic does not absorb sweeting. neither leather. as in the original cover.
on the other hand, fabric as in a cushion does.