Machine sewing... and sitting... . Contrary to what the ergonomics experts seem to say, about height and how high or low hands and forearms, etc. are... what determines how I can sit is eye-to-needle focus; and using magnification on eyeglasses does make things sharp, but it also changes the focal distance... eyes-to-needle. They can rattle on all they want about height of chair, platforms, feet, shoulders, hands, forearms.. but it all comes down to *it has to be in focus for MY eyes. Surgeons have high-quality actual tiny binocularsto wear over their glasses during surgery... but we quilters have to find the correct *in focus* distance from eyes-to-needle, and work from there. My machine is sitting on a 1 inch high board, which helps bringit up to the focal distance I need. Everything else has to work around that... height of chair, platform under feet, etc. I have asked several eye doctors about the focal distance as magnification of my glasses changes, and they all said the same thing.. **can I request 3.50X magnification for reading, and ask to have it focused at 16 inches.. the answer is NO.
SO... maybe you are trying to follow the ergonomic/back doctors advice, who dont take into consideration what your eyes need, and you are bending over to get things in focus?? Itsa thought...
I dont think hand-piecers are confined to hexagons and english paper piecing and other things.. like you said, any block can be made by hand. . I like to make oversized squares for HSTs and fourpatches, then they can be marked and stitched mindlessly on the pencil lines, and squared up afterwards. If you get all the HSTs and fourpatches very exact.. it helps with the rest of the block assembly.
Jinny Beyer also has a clever little pointy ruler for marking the *match points* where the stitching lines end... for triangles and other funny shaped pieces... it does need a 0.5 mechanical pencil for the small holes you mark the dots with.. I have a regular lead 0.5 pencil but need a yellow one for darker colors (perhaps Fons&Porter at joanns, they have that I think).
I think the important thing will be that you really LIKE the block(s) you pick to work on. Also, depending how many hours of 24/7 you are confined to bed... fix up some slightly angled desktop thing to use.. perhaps.. or save the marking and cutting for when you are out of bed.
I have always had to cut sitting in a wheelchair and I have found I cut more accurately, and apparently more safely (knocking on wood), than anyone I know. Good luck...