cutting mast

[Brion Toss]

Hello,
There is a chance that the taller mast, when cut down, will be the perfect stick for the Rawson. It is not a large chance. See, what makes a mast right for a boat is how well it can resist buckling, for a given load, over specific distances. Masts achieve stiffness by radius, by wall thickness, by unsupported length, by how they are attached at the bottom end, by how many wires are attached, and where, and by what they are made of. Did I leave anything out? Anyway, a shorter mast will be stiffer than a tall one, under the same load, but will yours be stiffer enough?
The only way to get a reliable answer is to run the proverbial numbers, calculating the expected maximum compression load on the shrouds, relative to mast length and configuration. The result will be expressed as the moments of inertia of the desired mast, usually as inches to the fourth power. If the moments you need are the same, or close, as the moments of the stick you have, yippee!
As for filling holes, they matter less the closer you are to deck, but you could put nicely shaped plates over them. Is the tall mast tapered? That could be significant.
Fair leads,
Brion Toss