I’d have to know more to give specific purchase recommendations, but in general:
That you have 208V indicates that your service is three-phase, which is usually a given anyway in commercial buildings.
There are two methods of measuring three phase with IoTaWatt Direct-Reference - using three voltage reference transformers, and Derived-Reference - using just one transformer. Both produce good results. You can use either with a standard IoTaWatt V5.
Given 10 HVAC units ranging from 50-150 Amps, what is the capacity of the Mains, and do the they use multiple cables for each leg (3 or 6 incoming service cables).
If the HVAC units do not use a neutral wire (no white conductor), then you can monitor each HVAC load with one CT. There are 100A and 200A models available.
At first glance it looks like you could do it all with one IoTaWatt, 1-3 reference transformers, a USB power supply, 3 mains CTs (probably 400A) and up to 12 individual circuit (HVAC unit) CTs of 100 or 200 Amps.
The IoTaWatt will save all of the data in fine detail, and you can plot it out from any local browser. You can also upload to an influxDB database with Grafana or Telegraff.
This should cost between $350-$400. If you need 400A mains CTs, there may be a lead time of a few weeks. I have a few right now, but doing a large 277V/480V industrial install and don’t know yet if I will need them all.
Hi-Res pictures of the load center with the circuits to be monitored labelled or otherwise identified would help to fine tune this. You would be well advised to have an electrician install the unit and the CTs.