2.65m high, 2.2m wide, 3.0m deep. 40deg angle. Height and/or angle could be adjusted with some work. Depth could easily be reduced by 50-60cm even if other dimensions kept, as it's deeper than it really needs to be.
T-Nuts at 20cm (moon board) spacing in 11 x 16 grid, so suits both bolt on and screw-on holds. Full detailed build instructions provided.
You'll need a vehicle large enough to accommodate 1.2m x 2.2m 18mm ply boards, and up to 3m long timber framing.