PBO doesn't work if you are using the same style fittings as the yachts use. This is a scale issue as the yacht style fittings are relatively too big.

The Skiffs here in Aus use PBO and they simply make their own stays by nailing two sailmakers thimbles at the right distance apart on a piece of wood and then they lay the pbo in loops between the thimbles. once finished they dip the thimbles in resin and put heat shrink over the whole lot.

it is a lot of work but pretty cool when finished. A better solution is to use Dynema as sidestays, once it has settled in the stretch is zero so they are as good as wire and the diameter is the same of very slightly bigger. make sure you use DSK 75 or 78 as anything lower will creep and stretch.