Yak Trolling Motor Questions (Size, Battery, Rigging...)

I got a KC Kayak that I'm going to rig with a transom mount minn Kota trolling motor and I've done a lot of reading but any input would be greatly appreciated. It seems that every decision is a trade of of some sort.

1) The motor- I'm getting an Endura 30lb or 40lb thrust. One advantage of the 30lb is a 30 inch shaft while the 40lb has a 36 inch thrust. I've read many people say buy the biggest motor possible but that will impact my battery decision later. I'll be using the motor more to increase my range than true trolling so I think the 30lb is plenty enough power.

2) The battery- Any opinions on here will be appreciated: 24 or 27 class? If I go 40lb thrust motor I have to go bigger. Is there a gold standard battery under $200? In pics of other folks rigging, I see plenty of exposed batteries. I'd prefer it fix a box like this:



3) The charger- I assume buying the minn kota charger I'm including a pic of would be fine but should I get a 7-stage charger instead?



4) Rigging- internal wire the battery to the front of the yak or can I get away with cooler/ice/drinks in the front to balance the weight? The simplicity of battery box in the back is attractive. Any feedback?

5) I'll be using more in freshwater with a handful of MS marsh trips a year and a LA marsh trip or 2 a year. As long as I thoroughly wash the shaft and remove the prop and rinse after each salt use, I should be ok right? Not really worried about warranty stuff since it's such a cheap motor.


Thanks in advance and here is a pic of yak for visual reference.