The worst part about trying to repair a Hobie 17 mast is no diamond wires.
With wires you could safely splice a top and bottom together at the spreader bar without adding a lot of weight.
The wires would do most of the work supporting the mast.
Without wires the splice would have to do all of the work.
It could be done, but it would add a lot of weight.
Welding heat can damage the strength of the alloy.