I think your sticking point is going to be finding a small enough sub-panel. It looks like your inverter is a simple DC in/Inverted AC out so I would be inclined to just go with that directly to a sub-panel and forgo an ATS. You can use your remote to turn it off and on when you need it.
It would be helpful to have a wiring diagram for the inverter. Did one come with it? Are the two inverter legs out independent, 1,000 watts each?
Easy to disconnect the converter, just take the lead off the breaker suppling the bottom power board along with the neutral and ground.
Steve and Andra
2012 F350 6.2 gasser SRW LB
Fab Fours front and rear in case we run into a rhino
2019 Northstar Laredo SC