I’ll do the great majority of it on ramps as I can get a lot more clearance with them, the suspension rebuild and under arches etc will be done on stands, with various other strategically placed pieces of wood…
Thanks for putting some words of wisdom on here though as too often I’ve seen people crawl under cars with it jacked on a small scissor jack!!
A car on 4 axle props with the jack left underneath as well is something I have done for numerous jobs, underseal, exhaust etc, and perfectly safe. But do not place them under the sills.