Thankyou Rod. I was hoping you would throw some knowledge my way. I owe everyone for chiming in, it is greatly appreciated.
I have the bluesea dualbus plus on the way, and yes, it's the nicest one I have seen. It will make future installs very easy.
I am using 2 gauge ancor marine battery cable for all the main connections. I did a calc and this nicely oversized for 100 amps, probably do 150, I will probably only ever need 60.
I will definately NOT use any existing power leads under the dash. they are undersized as it is, everything is done from a central breaker/relay box and it is fused for 30 amps. It's power is drawn from the main 60 amp breaker on the engine and is grounded to the engine as well. I took out my ballast tanks and spent some time tracing all the grounds and power leads. It seems that everything is grounded to the engine in some way, batteries, main dash power, everything.
Both the batteries (+) power terminate on two switches that are linked to each other. I found the manufacturer and they are rated at 275 amps continuous. the alternator/starter is linked in there as well. this will be where I tap my main (+) for the bus. This is preferable since I will only run on one battery, either battery that is and can switch everything off from there. Here's my battery switches that came stock, they are linked together with a busbar and that's where the alternator/starter wire comes in and the dash power draws from.
http://www.bepmarine.com/showproduct.cfm?productid=1 I am missing the breaker for the main bus and will have to pick one up.
If I have any ground loop problems with the current amp (200 watt), I will isolate it on one of the batteries, that is no problem.
Thanks again, I am grateful for the input.