Go with lithium, drop 130 pounds out of your boat, no need to go through all that. You can literally buy some on Amazon . I would watch some DIY Solar on YouTube he opens up all the Amazon ones and rates them . Some get as high or higher marks than the middle to higher tier brands at 3 times the price. 200ah on lithium phosphate you will have no worries. One big battery or 3 80ah . If your super worried about power get a PP charge you can fish for a half week that set up. Pricer option would be lithium cranking battery, but with that you would need to go high end to get that type of CCA in a safe housing. That option around 900.00, but the low dissipation until completely dead is unmatched by any AGM. If I recall correctly this battery was rated very high from DIY Solar Power with Will Prowse
Or for cranking this
https://www.monstermarinelithium.com/product-page/1700cca-cranking-lifepo4-the-beast-100ah
Hope that helps the new LifePo4 batteries are awesome no graph flickering etc … Plus combine it with a Power Pole Charge … Game over
