Hello, I have built one tiki and really happy with it, please find hereunder my comments hope it helps :
features, by order of importance imho :
- small nose rocker. approx 10cm on the last 500cm, the rest flat. really helps with chop & waves.
also, you can really glide flat, use most of the rail to track upwind because you know the nose will not pearl.
Making the nose rocker requires steam, patience, a template, swearing a bit and accepting the wood may spring back.
-a small fin a the back (TT 6cm say) ... without it is skids in chop and you can't hold the kite - to track upwind you use the edge, but fin avoids total looseness on chop
-thin rails, they really bite into the water to get you upwind (say 10mm if the center s 18mm)
-straight outline not too wide, I made mine 50cm it is too wide I feel at the tail, ridiing in chop gets a bit difficult - 46 is probably good
-bottom contours (eg concave; side rails) I did not bother and I think you can create more drag than good, it is difficult to plane a perfectly straight concave in a plank...
- wood type & glassing :
difficult to find paulownia (in europe), glassing on wood is not that easy (it does take in unevenly the resin, and can be quite heavy)
I used spurce and only varnished it with marine varnish.
But : I put ash veener (22x 0.9mm) sideways to prevent splitting.
That is after iit splitting in two a good bit away from the shore aha