A few questions come to mind:
1.) Do you have to have two different "Split" crews?
2.) With it being hot and humid.....Is working 8 hours on Saturday and Sunday out of the question?
Why not use weekend days and utilize them as regular work days? Not just "mow and go".
We work 8 hours - 7 days a week here and each guy has 2 days off during the week.
Monday: 5 guys working
Tuesday: 9 guys
Wed: 9 guys
Thurs: 9 guys
Friday: 6 guys + one part time guy (8 hours)
Sat: 4 guys
Sun: 4 guys
It can be done. Typically weekends are busy on golf courses and ownership doesn't like seeing guys on the course till 12:30 or 1:00 on Sat. or Sun. but when you have only a few guys nobody even notices them out there. Especially if they are holding a hose and watering hot spots.
3.) The bigger question is: Are you and your assistant willing to work 8 hours on Saturday or Sundays? My asst. has Friday and Sat. off and I have Sun. and Mondays off. Even though during the summer months I usually only take off Sundays (Family and laundry day

)
It was difficult for me to break the mold as well but my crew seems to be fresh for the 5 days they work. Even if their days off are Fri & Sat., Sat. & Sun or Sun. & Mon they seem to like it better than the typical one day off during the week and working 4 hours on Sat and Sunday's. If I was closed on Mondays (which I'm not) I would move the days around to maximize the work that could get done on Monday's.
4.) Is part time labor out of the question? Part time guys could help immensely. Ask the golf course superintendent from a neighboring course if any of his guys want to mow rough in the afternoons for you.
Just some ideas that may help.
Best of luck,
Jay Neunsinger, GCS
Tilden Park