Opinion only.
There is no benefit to leaving the bell housing on the block during disassembly. But there are drawbacks as you mentioned the extended length will make it less stable. More important, removing the bell housing, clutch and flywheel give you better access to the rear main bearing and those parts are easier to clean when they are off the block.
My biggest concern would be tipping it over. I would not consider using a three wheeled stand, thats just asking for trouble.
I wore steel capped shoes with metatarsal guards for 40 years, this is the reason. Heavy hunks of metal on your foot can really hurt.