Pentair Intelli Touch Control of Non-Pentair Analog Speed Control Pumps

Hello, I have a Pentair Intellitouch i9+3 but am not sure about the Pentair pumps and would like to consider another brand. I don't have any experience using the i9+3, so I'm looking for practical advice on its operation and configuration. We just bought the house and are becoming acclimated with the system.

The pool:

15-20k gallons with elevated spa and spa overflow
1 x Sta-rite 1hp or 1.5hp filter pump feeding a Pentair cartridge filter, and pentair filter
1 x pump for the polaris pool cleaner
1 x pump for spa jets
1 x pump for a separate water feature (not the spa overflow)
The piping from the pumps to the ground are 2", but seem to expand to 2.5" or 3" as they enter the ground

My questions:

1. What is the best way to control an analog pump (pumps that uses relay input combinations to control speed) with the intellitouch? I see there is a 2-speed motor low voltage relay on the i9+3. I'm thinking this would be fine for my setup since I only use one speed currently. In this case, I would wire the analog pump so it is constantly powered, then use the i9+3 high voltage filter pump relay and low voltage 2-speed relay to switch low voltage signals connected the analog pump low voltage speed inputs. I would then assign a high and low speed to the two analog pump input relay combinations. This seems doable and would preserve the different circuit logic programming.

2. My next question is, can the i9+3 filter pump logic have aux relays assigned to it so analog pump speeds can be controlled? If I can do this, I would, so I can setup more than 2 speeds in the future. Although, I am not sure how this would affect other circuit logic.

3. How does the intellitouch system utilize all the different speeds offered by the Pentair pumps? Eight speeds seems like overkill.

4. A pool guy said I should consider combining all my pumps into one pump. I guess this is where the eight speeds come in? If I did this, how would I balance the flow to each load? Would you just turn up the pump until the system reaches the "knee of the system head curve" for each combination of loads? I saw there is a Pentair heater bypass valve for high flow - assuming I would want this for this case.

Thanks for your help, Rob

bump

You're going to need one of our experts on SWCGs and pumps to advise you. That's above my paygrade.