Little finishing tips on setup

Hi all,
I’m completely new here, I have bought a maslow kit like 2 years ago and now finally I’m installing it.
My shed is unfortunately a bit small, I’m building against the wall, and that wall is 2.8 meter wide by 2.2 meter high. this would be 9.18 feet wide x 7.2 feet high.
I have chosen from the info I found on the forum for haveing it sloped 12 degrees (also because with 15 I cant open the door properly ;)).
I will place the motors as far to the sides as is possible. The tips I’m looking for is how high should I place the bottom bar on which the wood that will rest.