I don't personally understand the 4th guy... I've at most run 3 guys and 2 mow 1 trims and whoever gets done first edges the sidewalks/drives the next guy done grabs the blower and cleans up...efficiency! If you have other lawns close to each other then send the guys mowing ahead of the others and the others will catch up to them, you will get them done faster, no need for a 3rd or 4th guy standing around waiting for the others. If you must run 4 guys, then you should be doing a FULL service each time your at each lawn. 2 guys mowing 1 guy trimming and the 4th guy weeding and trimming shrubs as needed at each lawn. Charge more for a full service lawn care.