I did something similar to David for my aft fuselage. I made some plywood pieces to perform as a platform. What you can't see in the attached pics is that I put pieces of 1" foam insulation from HD aviation supply under the plywood.
This worked out great.
For the seat area where I have to climb in I use a combination of Harbor Freight moving blankets and 1" boards to distribute my weight. I used some of the old crate wood for these pieces. I put a moving blanket on the seat pan, then the boards and then another moving blanket. That way I'm protecting my seat area and the plane's.
2020 Donation Paid
Titan IOX-370, Dual PMAGs, 9.6:1 Pistons, FM-150
RV-7 Fuselage in progress
* Cabin Interior - In progress
RV-7 SB Wings
* Both Wings fully skinned
* Fuel Tanks Complete - No leaks finally
* Ailerons Complete
* Flaps Complete
RV-7 Empennage - Complete (a little fiberglass work left)
Vans Training Kit # 2 - Complete
RV-7 Preview Plans
Vans Training Kit #1 - Complete
EAA Sheet Metal Class - Complete