Dear Brian,
The side-cut tapers you are discussing are generally used on yacht size sections - 4 and 5 mm wall thickness typically.
For a dinghy-size mast with thin walls, the front- cut is the way to go.
Do not just cut a straight wedge there needs to be a bit of either convex or "S" curve in it to obviate a "garfish" look to the finished taper.
Some radically tapered one tonner masts in the eighties, had four cut tapers with very intricate curves and allowances for distortion. Even then the hydraulic press came in for some work to ensure a sraight topmast after everthing was welded-in.
I am not surprised that you can get no free specific information!
Mast builders will have already used up and scrapped several pieces of section to establish the right number and configuration of cuts for each profile ands they guard these data jealously.
I inherited a whole sheaf of section and vessel specific taper cut profiles when I bought a mast makers archive and, let me tell you, there is nothing straight about the cut lines produced by the tables of offsets!
Do not expect to get yours right first time. You may get away with stitch-welding the taper say 20 mm weld then 10 mm space then 20 mm weld again. leave the spaces they will not harm the bend characteristics.
I have seen dinghy tapers with riveted straps holding the taper closed and they worked ok!
This may be what you have to do after you have cut your existing section up in disgust and thrown it in the bin.
Good luck and regards,
Joe Henderson.
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