I just bought a pair of 2200 units, and plan to use them to power my RV-Car Hauler project.
The standard plugs on the Non Companion model, and the standard plug on the Companion model are both fused with a 20 amp breaker.
The 30 amp plug, as well as the Parallel ports on both units are not run through a breaker (at all). This allows the factory recommended pairing to actually exceed 30 amps transiently without tripping a breaker. If you use the HF unit, you will be limited to 30 amps unnecessarily actually.
I find this aspect interesting, that the pair of 2200 can kick out 37 amps transiently, so Honda DOESN'T fuse the "30 amp" plug on the companion.
Since my RV has a fuse box, I will simply use a parallel plug kit off amazon to tie my two non-companion units together, and not be limited to 30 amps either.
(Atima Generator Extension Power Cord Cable AGC103 Parallel Kit)
By the way: As I set this up, I have also bought a pair of hour meters to install on the units, ones triggered by 12V, not induction of spark plug wire and not relying on an internal battery in the meter. This will allow for proper maintenance.
(Searon DC 12V 24V 36V 48V 60V 72V Mechanical Engine Hour Meter Generator Hourmeter 6-80 Volt)
Honda once sold a Honda labelled box similar to the HF one mentioned, but UL approval was available only if they also approved the gensets (logical) but Honda didn't want to go that route. So Gen Tran still makes a clone of this, not labelled Honda, but Honda only sells the parallel wire sets, not a full kit.
Once nice tip for any of the parrallel kits is that the ground lead that has to be fastened to the front panel is tied to the ground of the standard plugs. So, to keep things easy and plug-n-play quickly, you can put that green lead into a standard plug using JUST the ground wire, and plug it into one of the two outlets to make taking the wire harness on and off very simple.
Amazon Wire Harness to Plug:
Amazon Hour Meter: