Yes a horizontal rack on the bed-ways has worked for me, some of the time, depending on the job in hand - e.g. spindle work was often a little awkward.
I currently use a free standing horizontal rack on castors. However I still find that I simply place the tool I'm using on the bed-ways in between times until I want to swap over to another.
So a flat on the largest diameter of the handle seems to me to be a good thing. But fair point, I should trial it for comfort before modifying a tool(s) from my 'armoury' - don't believe it would be an issue for me though.