I have helped several people install this two-pump method, which works very well. I have a similar system, but mine uses two wells instead of one well and a booster pump. I have a 1/3HP sub in a well that supplies the Geo system. Then if the house uses water there is another well with a 1/2HP sub that comes on to supply the added water needed.
My 3 ton Geo system only requires 4 GPM flow. If your friends Geo really needs 6-8 GPM per ton, plus another 10 GPM for the house, that would take 42 GPM. Even just delivering 20 PSI to the Geo system, from a lift of 80’, that would take a 2HP sub. What “new rule” are you talking about that won’t allow the use of a 2HP? That would also be fairly expensive to use for pumping to a Geo system.
You need to find out the exact GPM per ton that is needed, and do a pump test to see at what level the well will be when pumping this amount. If you can do this with 4 GPM per ton and the pumping level is 60’ instead of 80’, it would cut the pump size in half to a 1HP, which would also cut the pumping cost for the Geo in half.
To be even more efficient, I also take the water needed for the house from the discharge side of the Geo unit. When cooling the water to the house is 10-15 degrees higher than well water temperature. This actually cuts down on the cost of producing hot water as it feed the water heater with 10 degree warmer water. And many times the cold water at 82-85 degrees is warm enough that no hot water is used during showers. If I want a cold shower I just have to turn off the AC unit before showering, but I don’t like cold showers. There is usually enough cool water in the lines to get a glass of cold water when needed. Other than that the toilets, sinks, washing machine, etc., don’t care if the water is a little warmer coming in.
Taking the house water off the discharge side of the Geo system reduces the total demand by 10-15 GPM. So now if you can use 4 GPM per ton and take the house use off of the Geo, you only need a 16 GPM pump. At 80’ and 20 PSI that would only take a 3/4HP well pump. A CSV can take a ¾ HP load down to 1/2HP when using less water, now we have a system that use 25% of what a 2HP well pump would do.
Of course you will need about a 3/4HP jet pump to boost the 20 PSI coming from the well pump to the Geo system up to 50-60 PSI for the house. But the jet pump will only run maybe 30 minutes a day to supply the house, while the little 3/4HP well pump might run 18 hours a day for the Geo unit. You still want to keep the well pump as small as possible, but this two-pump system can reduce the pumping cost for the Geo by more than 50%.