Thanks for the comments and happy to answer any questions. After a couple seasons use I'm pleased overall and no regrets about choosing this installation option.
After 2 years of use I'm honestly not sure if i could have used a shorter shaft but think it will be close. When I purchased the Kraken the price difference between the 75" and the 90" was negligible and the way i was mounting the extra length didn't matter so I went with the 90". They said could cut it if it turned out to be too long but the thought has never crossed my mind.
The 90" never cavitates and a couple of times I was practically taking water over the bow... In calm water I usually set the depth collar at about 15" - 20" which helps give me leverage when stowing it and I've never noticed it cavitate due to a small boat wake.
Keeping the light and the cleat was one of the main reasons I installed it this way. I need to step one foot over the rail on the pulpit to step on and hold down the release pedal which can be awkward while trying to lift the motor head, especially if choppy, but I just turned 66 with a gimpy shoulder and I manage it OK.