I'm surprised you haven't got straight forward replies on this. Roof mounting is better by far than any other solutiion.
I watched moems video and it was good of him to put it up.It was well engineered but i felt the positioning of the reels was poor and would be awkward to reel in, and possibly awkward to walk away from with the hose following.
Mounting reels in the rook wasn't my idea, and i see that moem says this (his)was 2.5yrs ago.There have been several quite brilliant examples of thix posted on here.One had a turret.
I feel that the turret is not necessary.The criteria is that on arrival at a job you grab the pole. put the harness over your shoulder and walk away.You should't even notice any pull of the trailing hose.
On completion you walk back and wind in.The winding in by handle (i'm electric) should not involve any bending or strecting and be very easy to reach.The reel should face the direction of the hose- unless of course you have a roller guide.
All that's really needed are some cross members in the roof, and then the reel, usually upside down mounted to this.