Additional to my footstool I use a cushion on my left leg, that I made myself. A Guitar teacher to,d me to put something flexibel on my leg, so that I am not too fixed in one position. This comment made sense to me, and when I was at home I took a thick wool scarf and made a roll out of it, than I sewed it together and sewed a rubber sheet on it. This became a very useful tool to me. The footrest is now on a very low level, so that my back is not too screwed.