By specs 65 lbs should be fine although generally the more the better. I don't know about Jarvis Walker (is that the watersnake). I have an old MK 55lb 2013 model in my 4.2 tinnie and it is sufficient although when the tide is running fast and the wind is blowing in the same direction it struggles, I've heard more recent models hold better.
On the Allison I run a 36v 108 lb Motor Guide and it holds surprisingly well in choppy seas however it's big downfall is you need to be able to aee the lights on the unit itself to know what it is doing, even then you don't know at what speed setting it has been set as the remote doesn't have a screen umlike the MK.
Whichever you get it will be a game changer to your fishing.