my f-550 has an 11ft 'glass body, with a sectional sliding top cover.
left front compartment
CM top box, 26" wide x 18" deep, holds basic hand tools from 1/4" - 1 5/8" 3/8" dr & 1/2" dr. cordless impact, along side of the box, large channellocks, torque mutiplier, long 3/8" dr ext, long 1/2" dr breaker bar
2nd left compartment
mac side box, with air tools, grinding/cutoff wheels, large snap ring pliers upright next to the box, i keep hammers, prybars, 3/4" dr handle
3rd left compartment
3/4" dr sockets, ratchet & breakerbar heads, 1/4"dr socket set, "electrical box" DVM, test lights, drills, taps, dies, extractors, seal and bushing drivers,
right front compartment
vaccuum pump, a/c guages, HVAC dye kit, a/c thermometer, temp gun.
bed of the truck
air compressor, porta torch set, grease gun, drain pan, hitch mounted vise
both the toolboxes are secured to the body so they cant move, 3/4" dr sockets are in 4" x18" deep acrobins.
if i was to do it over again, i'd replace the top box with 2 & 3 drawer center boxes for more storage. any heavily loaded toolbox in a service truck isnt going to last long before they start breaking apart at the seams.