Thanks for all the suggestions, and for letting me know others have the problem. I have been taking off the breast beam and knee beam, but I'm on the tall side and still too far away for my back to be comfortable. I thought about draping my legs over the cloth beam, but couldn't figure out how I would extricate myself. :-)
I think raising the entire harness assembly with shaft holders and standing, and finding a 4 legged bench that straddles the bottom beam and the treadles (if I want to sit) is the answer. Thanks Sara.
Part of the reason I haven't done this is that I don't have shaft holders. I tried to get them from the Toika dealer in the US and they weren't able to provide them. Sara, does you shop cary shaft holders that fit Toika shafts? They are wider than Glimrakra.