RE: Prestwich Makara with Zen7 anyone?
I glassed in another tube on my hull so the stuffing tube slide down it if for any reason I need to change it out.
I know just glue them in using an evostick serious stuff adhesive which comes in a tube and is shock proof and give a slight bit of movement.
The centre line of the shaft needs to be 13mm up on the transom. I set my runner so it's in line with my stringer. 2.5" from the centre line of the boat. I run double rudders on mine so this might me different for a single.
Get a few opinions and go from there. Nothing will be wrong it's just it could work better. Im finding better ways to keep the makara fast and stable that's part of the fun of boating!! Messing!!!