Thoughts on Phoenix 12/800 vs 12/1200 for use with 125AH Battery?

Looking to install an inverter into Ute canopy, I’m thinking the 12/1200 might be too large for my 125AH agm battery? I’ll be using it for charging cordless drill and battery chain saw batteries, laptop, Dyson chordless vac, etc (ie. no coffee machines or microwaves!).

Also, with the main DC terminals on these inverters, with the flex conductor, do you use large bootlaces or just twist the wire and put it in?

Edit: one more question: can I use any toggle switch for the remote switch (appropriately rated as per the manual)? I don’t think I’ll have the room for the remote switch plate…

Thanks.