Hoping to get a little advice here. I'm planning to do some preventive maintance on my boat and I'd like to replace my batteries. I have a 2000 Gulfstream with twin 150 Yamaha SWSII. The current system has dual batteries running through two battery switches. Should I replace the batteries with starting or dual purpose? I spoke with a local dealer and they stated that I should use a dual purpose while Grady recommended the use of staring batteries. I just want to make sure that I choose something that can start the engines and handle the electronics.