084 Motor Stand Questions

[Bart]

Okay, I finally am almost ready to start on my stand for the 084 motor, the last time I built my stand for my 2 stroke Cuyuna, I didn't have an Aluminum welder. so I was stuck to mounting it on the ribs that were already on the boat. on 16" centers.
But now I have widened the hull, and I can place the ribs at any distance for the stand I will be making.
I am leaning towards fabing up a 3 point stand, (at the moment I am waiting for the motor mount bushings...)
as far as the height, goes. it all depends on the prop radius. really don't want to leave much of it below the gunnel. it might look a little high when I am done.. the 2 props I have at the moment....are a 4 blade ultra prop w 60" radius, & a 3 blade warp drive w 57" radius.. but I have been hearing good stories about the 67" whirlwinds...

the question I have at the moment, what would be a good distance to have the bottom stringers for good stability?
Now that at the I can choose my width, and make it a little more stable and user friendly,