It does not matter which H3, but if you have a preference just be certain (since you have been dealing with folks who seem to not know what they are doing) that the Port (Port 1, I think) clearly indicated on the switch that is designated as the "Power Inserter" port is going to one or the other Hopper, so if you prefer, you can tell them you want the power inseter at the Hopper of your choice, especially if there is a power outlets available at one Hopper but not the other.
Most tech just presume to put the inserter in the main living area like room because most people don't want the inserter cluttering their secondary rooms if it is a bedroom, etc.
Good Luck, and I feel for what you went throuhg. Your situation is why I have come to this site for years so that a Tech who does not know what they are doing aint a gonna touch my system

.