The trouble with an X type bench( Ihave one!) is that you better sit right in the middle, and not lean out to get something, or you will tip it! I did, and went into the wall ! I had to set it to the tallest it would go so I could see my screen on the PSR-2000 keyboard. I am very short ( 5 ft 4) and have bi-focals to boot!
If I had it to do over, I would use a stool with a back rest like Gary Diamond uses.