I have placed a couple of mast steps in the bottom of the hull, in different places because if paddling solo you seem to generally use the front seat (going backwards) and if tandem you obviously use the normal seating thus the rig needs to be out of the way for each arrangement, they are made from 2*3/4inch ply blocks one with the hole drilled in and glued to the other as a base, these were glued to the hull and then an epoxy fillet placed around the edge, I did not want to screw them in a) so that they are not a permanent feature and b) if they rip out then the hull should not be holed.
The rig slips into a larger diameter tube, this I have just strapped to either thwart, seems to do the trick
I will try the rig without a leeboard first but I guess I will only be able to run with the wind without it, I intend fitting both leeboard and rudder
Additionally I drilled out both stems and bushed the hole with 15mm copper pipe, this is to secure rope for grab lines that can also be used for carrying or tie-downs
Not impressed with my paintwork now, had lots of issues with it bubbling up so I have had to scrape it back, fill and repaint but its not the weather to be doing painting so its been purely to waterproof it, I will have to wait until next year to rub it all back and get some better paint on