need help mounting Bow Mount TM

I have a new Alumacraft MV1648 and it has not been in the water yet so I am unsure how to mount my TM. If I understand right the TM shaft should sit straight up and down ( like this | ). Now the question is the existing bow deck slants down towards the stern maybe and 1 - 1 1/2" overall as compared to the top rail. I was thinking that if I just follow the bow deck it might cause the motor shaft to be off and also slant towards the stern ( like this \ ) I don't have an opportunity to put the boat in the water prior because I don't have any other means of propulsion right now. Anyone have any ideas on how I should mount this? or How to figure out what part of the boat should be level (if any) when afloat so I can use that as a reference.

Right now I adjusted the tongue jack on the trailer to make the bottom flat portion of the boat level. Is this a good starting point? Does that part of the boat sit level in the water when the boat is empty?

I know I am probably putting a little too much thought into it but I do everything that way! :lol: I just want the motor to work as efficient as possible.

Put the boat in the water - it is OK is the TM is not at a perfect 90* (in fact, as people move in the boat it will constantly change anyway

and when you are up on the bow deck operating it, it is probably closer to perpendicular than what you are measuring on the trailer.

I'm just gonna put it right on the deck and if it need adjustments I'll change it. Thanks!

Now I'm trying to figure out weight distribution.