You can put the 1093's clamps on any pos and neg post you can get at. In fact you can put the pos clamp on a pos post and the the neg clamp on the rig's frame like it says to do :) You can leave the solar on while you are charging with the 1093.
You can probably rearrange the battery links so your most "balanced" pos and neg are up front.
If you get a Trimetric then its shunt neg will go to the neg battery post and you will need to connect the 1093's clamp to the outer end of the shunt for the Trimetric to show what the 1093 is doing along with the solar neg and the rig's negs.
You can solve a lot of that by balancing the batteries and run a set of wires from the proper posts to a pos bus and the shunt as the neg bus. One guy with a four battery tray like that put two holes in the "roof" of the compartment where the tray is and ran the wires up through the holes to the busses. That way he didn't have to worry about getting the tray all the way out anymore.
BTW the little gen will run the 1093 but won't have much left over to run anything else at the same time until amps have tapered down quite a bit from the initial 40 amps.
Also the 40 amps will take a long time to recharge four batts from 50-90%SOC maybe 6 hours. My 100 amp charger can do that in under three hours but needs a bigger gen of course. Its the old story, noisy big gen for a short time or quiet small gen for a long time (unless you have a big Honda which is quiet and fast)
