SUM, Don't forget the Fuel and oil costs. And the stop charges for delivery & pickup, sometimes I just drive the lift back if its only a few miles, Foam filled tires aren't very road friendly. And of course wash the lift clean and fill the tank to aviod back charges.
I found I could insure rentals cheaper than the Rental company at ~4 months rent of ANY mobile equipment, mini-hoe,skidder,& lift, but just one machine at a time.
On commercial jobs tire damage can add up in a hurry, calcium filled tires really limit your choices of service providers here, and really slow service possible during farming season.
A. Could you do the Job with out the lift and or the rented scaffold? I. e. the renting the equipent ought to LOWER the per brick $ for YOU.... At 22 working days a month( days only with out rain, snow, wind and or to hot) max, you're north of ~15 dollars and hour and you are "losing" the person who is camping out on the lift, For small crews the machine can become an early retirement option while drawing pay... Just as stupid is not using it when it'd pay because of fuel costs... You might want to consider actually doubling down and hiring(Assign an apprentice mason? retired/partially disabled laborer/operator part time) a person to operate the machine on days you're building/moving scaffold to keep laying...
As an employee unfortunately, a majority of work places, the more power equipement has lead to less tending behind the hop as the "operator(s)" does his bus route on his ten ton wheel chair, the remaining labor shift into a lower gear.
Rereading the post, you must have a small crew, 20K/month is 2 guys and a helper, this could be a rope and pulley job... 4000 lbs of brick a day and 3000 mortar, & 1000 lbs of scaffold is 20 fifty pound lifts an hour.... or build it scaffold high with what you own, then call in the rented scaffold and lift, on a tight lot get the smallest machine you can that''ll work
I've never had a GC I'd trust with my actual per M cost, I just bid the building(work), I've had to quit giving the local low lives even my estimates of the Units prequired, just a $ number for materials and $ for labor,(they'd use my #s and the I'll lay those brick 500.00 cheaper mason) How can letting the GC in on your pricing ever end well for you? Every wall is different, time of year is HUGE factor for me for labor cost/unit, and still the locals allways procrasinate on booking the fall work every year