Desert Scruff, et al,
It is my opinion that a re-settable circuit breaker be placed between the Truck battery and the ACR and another between the house battery bank and the ACR. I believe that is consistent with the Blue Sea recommendations for installation. It is further my opinion that 8 AWG wire is too small to run between the truck and the camper unless the camper house batteries are kept mostly charged by solar or ground power.
The circuit breakers should be sized for the wire size chosen. I used the spreadsheet for short term current to determine wire size for my truck to camper connection. I wound up using 6/2 duplex boat cable that I ordered from PKYS.
Based on comments I have seen in these forums I assumed a worst case of 80A for 10 min for my calculations. I think that is very conservative, maybe too conservative.
My calculations show that for an 80 A load for 10 minutes a minimum wire size of about 5 AWG is needed, I would have gone with 4 AWG at time of purchase but the largest duplex wire from PKYS was 6/2. Thinking more about this since then I am comfortable with 6/2.
I thought about how my solar has been working and how likely or unlikely it might be that I would actually experience an 80A load for 10 minutes. That caused me to buy a battery monitor for the truck battery (I already have one on the camper house battery bank) that way I can compare differences in charge.
I also put in the Blue Sea ML-ACR with remote along with Blue Sea series 285 80A circuit breakers (on each battery bank as described above). The battery monitors allow me to decide how the system operates, say if the load differential is too big I will just isolate the batteries (so I don't fry the wires) until the solar brings up the house batteries. This set-up also allows me to jump the truck battery from the camper house battery bank if I need to (jumping is less an issue because the truck usually starts with less than 6 seconds of cranking)
Caveat: I just finished installing all of this stuff so do not yet have real time field use on it.
Therefore, I defer to any comments on this from ntqsd, Rando, or Vic as I believe they are a bit more experienced and knowledgeable about this stuff (particularly since I may be too conservative).
I hope this info is helpful.
Craig
P.S. I did not specifically answer your question about replacing the automatic resetting breaker. I don't know enough about their operation (yet) and it bothers me that on a circuit that could fry from over current that they auto-reset. I want visual indications of issues (popped breaker) and ability to manually open (or close) the circuit. I don't see how I get that from the auto-reset devices.