I'm kinda in the same boat the battery set up I want would be about 2000 dollars and dollar for dollar it's about the same just a lot up front. Honestly I'll probably go the agm's and just be happy. Momma let me buy the new boat and want to upgrade batteries, it came with interstate 27s for free but wanted to charge me 300 a piece to upgrade to 31s I said I'll do it myself at that price.
Just curious why do you have 2 starting batteries?
How was the fishing? I'm itching to get back out but the weekend temps might keep me home. 35 for a day time temp doesn't sound fun right now