The unit specs show 45 kW of resistance heat which would be a far greater load than 20 tons of cooling. No indication of indoor fan hp, but 5hp or less for 8000 cfm would cover it. Round numbers, 50 kW per unit when in heating mode.
If you run both units to warm the place up, the demand would push 100kW from the 2 units alone. Assuming the facility sees sporadic use, the demand charge on your power bill will likely far exceed the electrical use charge so its important that you understand up front what the demand charges are in your area.
For example, with Duke Energy where I live, if I were to run a 100kW demand for 20 minutes and never turn the units on again, I'd have a $640 demand charge bill every month for a year. Drive 20 miles up the road where power comes from a co-op and the same 100kW demand would give you a $1100 demand charge bill each month for a year.
90 kW of electric heat is 307,000 btu/hr. I'd look seriously at using a pair of 20 ton gas-pac units and operate them on propane if natural gas isn't available in your location. Resistance heat is about the most expensive heat in general, and this is particularly true on commercial services subject to demand and the use is somewhat sporadic.
A lot of utility companies offer what they term a small commercial service where there is no demand charge as long as you don't exceed 35kW. It would be worthwhile to see if that's available from your utility. A pair of the more efficient 20 ton A/C units will push 35kW when running fully loaded. It could be worthwhile to have a load calculation run to make certain what you really need if the current pair of 20T units are just an offhand guess. If a pair of 15's or 17.5's would do the job, you might be able to slide into the small commercial category if your utility offers such.
IMO, the typical large portable or spot cooling unit is ridiculously expensive for what you get. AFAIK, equipment of this type is still immune from any energy efficiency regulations and efficiency is way down the list of their priorities. I worked in the hvac business for 20+ years, and any of these units I've seen are also extremely noisy.
A reputable hvac contractor familiar with commercial scale work can likely work with you to give you a heating and cooling system that would operate at far lower cost than the portables, and do it at a price that's not much different than the cost of the energy hogs being discussed.
