It works. Install the parallel cables first between both units. Start up the Eu1000i first. Then start up the Eu2000i. I start both of mine up in Eco mode, and run them about 2 minutes before I take them out of Eco mode and plug the shore power cable in. Then I go inside and turn on the A/C in low fan mode. Once the A/C fires up and the electrical load has stabilized, I'll set the thermostat to 68 F, and then place the Eu2000i only in Eco mode, leaving the EU1000i in normal mode. Both of them loaf, once the compressor has gotten up and running. The object of the temp settings is to not have the A/C cycling on and off, pulling heavy start loads on the generators. Get it running and keep in running by temp control.
I don't recommend doing this, to anyone else, unless you have some basic understanding of electricity, current, amps drawn, voltage drops, and electrical motor and compressor start up current draws.
There are kits out there to pair 3 Honda Eu1000I's together for 3000 Watts, so they can be synched.