adding 2nd battery...wiring Q

so i bought a kinetik battery to add in my trunk to help with the light dimming from the system when its beating. i have since added air susp and def think i need to do this since that is an added 48A load. i have a new interstate main battery with 0ga wire run into a (3in/4out) fused d-block currently. im going back and forth with how exactly i should wire in this 2nd battery. i will run a 0ga ground run from the battery to the trunk for sure. im guessing i can run the 0ga wire from the kinetik to another inlet on the dblock with the sgp20 isolator in-line? or would it be better to put the battery inline on the power wire from the main battery?

run it off the distribution block. that's what it's there for.

I would run it with an isolator to keep both batteries apart. You can kill the 2nd battery and still be able to start your car with the 1st one.

Running both batteries together will still make your lights dim which is what your trying to limit.

I had 3 batteries in one of my cars just for the stereo and nothing else.

One more thing when having batteries in-line, when one goes bad it will drain and kill the 2nd without warning.