J1772 stations advertise their maximum current rate on the pilot signal of the J1772 connector, and the SR/F listens to this pilot signal and limits its current draw to what the J1772 station advertises. So there is absolutely no need for a limiting rate if using J1772 stations.
The same goes for the type 2 mannekes version of the SR/F we have here in Europe. The signaling is exactly the same. The EVSE signals the maximum current and the SR/F limits the current drawn from the EVSE.
As Don already explained most J1772 stations can do between 5.5 and 7 kW. The premium version can make better use of these stations at 5.8 kW total, versus the standard version which can only draw 2.9 kW.
For the premium : if the SR/F would be at 20% you can get back up to 70% in just an hour
Getting the rapid charger module would not seen sensible to you as you would lose the "tank" storage compartment, forcing you to use a topcase, side cases or a backpack. All of which ruin the beautiful look of the bike
BTW my dealer told me also that you can always add the second charger and even the second charger AND the rapid charger afterwards but obviously it would cost more as the wiring harness of the chargers need to be replaced.