Here is another method to try.
I use the "Sit & Spin" method because I think its is the easier and more graceful. Graceful is important since there is almost always an audience when you exit or enter the SLC.
To enter:
1. Sit om the fiberglass door threshold as far back as possible.
2. Pivot on your butt and bend your legs to clear the front of the threshold.
3. With your right hand on the center console and the other hand on the fiberglass door threshold, extend your legs into the foot well.
4. Using your arms, shift your butt over and down into the seat.
To exit:
1. Put one hand on the center console and the other on the fiberglass door threshold
2. In one smooth motion, use your your arms to lift yourself out of the seat, use your feet to push on the cross brace on the floor, and shift your butt onto the fiberglass door threshold.
3. Pivot on your butt and bend your legs to clear the front of the threshold.
4. Stand proud!
W/O having a GT40 within arm's reach to confirm it, 'twould appear this method ought to work well entering and exiting GT 40s as well.