The place we're in now, we bought back in 2001 and we just paid it off, this past April. We were late paying it off, because of covid.
Besides moving into this place, we moved from our original shop in our old attic and basement, to a 700 sq ft shop, to a 4,000 sq ft shop, then to a 13,400 sq ft shop and now our present 10,800 sq ft shop, but 2,100 sq ft of that is a rental unit next door. While we could spread out like crazy in almost all of the places, this last one, I made boxes in Illy, representing all the equipment, cabinets, desks, counters, work stations of their sizes with needed real estate to maneuver around them comfortably and still have open work areas to create the best work flow, we could figure out. Since then, the walls have closed in on us, but it's still functional.
Your vehicle bay should have about 3' on each side of the largest vehicle you feel comfortable doing, so you have room for ladders, in case you hafta go up high. Our bay is 20' wide with about 2' tables going up & down the walls at one end for about 50' and substrate racks which stick out about 4' 1/2 way down and 2' wide shelves on the other side with lotsa tools and work stations. Our bays combines are 110' long.
Years ago, before the computers, I did the same thing on a graphed piece of paper and put all the pieces on cut-out pieces of paper and labeled them. Using the computer was soooo much faster and accurate.