I would like one for the hook7 if you're selling them Ernest 

Don't want to sell due to possible 1099k impact next year, but you can have one if you're willing to pick up from Union City.

If your unit is having issues with fogging, you can try one of these...
https://www.amazon.com/CamKix-Anti-Fog-Inserts-Housing-Systems/dp/B00KIADIRO

The fogging issue makes my GoPro unusable underwater because of the condensation. I think these moisture absorbent inserts work well if you don't have a lot of moisture inside the unit. But if it has a big leak, then I don't think the inserts would help.

Looks like a fun ride. My AI with the Suzuki 2.5hp max out at 7-8mph. You getting 8mph for free seems like a great deal. I noticed your bow did not submerge at all. I remember the last time I sailed my AI (probably over 10 years ago) in Alameda, the bow kept submerging. Did you put counter weight on the back of the kayak? Also, what is that thing on the port side? Looks like a haka with a bait tube.

I registered my AI in 2018 (I think). I told them my original purchase date was 2012. They ended up charging fees from 2012 to 2018, plus some penalty for late fees. They didn't know what to do with my request to register my kayak, but insisted on charging me late fees because their system said so. I walked out of the Hayward DMV with $500+ less in my pocket. Honesty is not rewarded at the DMV. You do what is right for you, but I wish I knew I what know now.

No body cares if your kayak is registered if you don't put a motor on it. I've been through two boarding report by the Coastguard before I registered my AI. I had an electric motor installed. They looked at it as a safety feature and never bothered me about the lack of registration. I only registered my AI because I wanted to install a gas outboard motor.

I will not put a lithium battery out of reach no matter what chemistry it is. I want to be able to toss it over board if it starts smoking. I would not want it to catch fire while sitting in my plastic kayak. Lithium fire is intense and spreads quick. If it ever goes off, I want to just grab it and toss it. I would not put it in the front hatch or the back hatch where I won't be able to notice the smoke or fire until it is too late. For my FF, I install it in the mid-hatch. For my electric motor, I put it in the tank well behind my seat.

I love lithium batteries. There are many advantages over SLA. But people that use lithium batteries need to be abundantly clear on how dangerous they can become. Shorting a lithium battery will cause it to catch fire intensely no matter what chemistry it is. Do I have to show you guys what happens when they get shorted?  One might say you trust your installation to be perfect and everything is connected correctly. That's great, but you can't control the unexpected. Some conductive material may fall over the battery and touch both terminals. (ie, the aluminum foil you wrapped your sandwich with.)  The device your battery is connected to may have a problem and cause your battery to short out. This is very common. There are ways to prevent or minimize these risks. Just saying that it's better to be prepared.

In order to figure out how big of a battery you'd need, you have to know how much your motor draws, and how many hours you'd like it to last.
Your 54ah battery only lasted 5 hours means your motor (at the settings you used) on average drew 10.8a per hour. If you want it to last 8 hours, you'd need a 86.4ah battery. 108ah if you want it to last 10 hours.

When you get a different motor, the draw is going to be different, then the size of battery you'd need is also different. You should get an amp meter to help you determine how much your motor draws, so you can pick the right size battery.

Many cheap motors use power resistors instead of PWM. Those power resistors are inefficient and would eat up more juice than if it had a PWM. If your motor doesn't have one built in, you should consider modding it to use a PWM. It would help you save a lot of power if you go slow.
PWM only helps if you don't go full blast.

The faster you run the motor, the higher the draw. The amount of power you give the motor vs the speed gain is not proportional. To go 3mph your motor might draw 15a, but to go 3.5mph it might require 25a. The speed vs power consumption is not a linear increase.

I troll with a small 18lb thrust WaterSnake. On my Revo 13, I can troll at 2-2.2mph with 3a draw. I built my own battery packs with whatever capacity I need. My tiny 30ah battery would last me 10 hours. The motor and battery together weight 13.5lbs.

What I'm trying to say is, the motor you select, the amount of time you want to last, and the way you use it, would determine how big of a battery you'd need.

A rough estimate of power draw can be determined by the thrust rating. They are roughly equivalent. So if you have a 55 lb thrust motor, it would roughly draw 55a per hour at top speed.

Good luck in your search.

Your waist puller idea reminded of this thread...power wheels, I always wanted one as a kid!
http://www.norcalkayakanglers.com/index.php?topic=70447.msg797911#msg797911

I wanna build one of these for carrying my AI up/down the slope at Rockaway. I don't think the Hot Wheels motor can handle that steep slope. Looked at some options but not decided on one.