Replacing Barient 27 with Lewmar 46 - Best Method?

[dbcreed]

I am preparing to replace two 1978-era Barient 27 Self-tailing winches with two new Lewmar 46 Self-tailing bronze winches (on a 1978 CSY 37). The bolt patterns are slightly different. What is the best way to accommodate the new bolt pattern? Rotate the installation to go through a new spot? Fill existing holes with epoxy and silica mix? Other idea?
Barient bolt circle diameter 143mm with 9.5mm bolts.
Lewmar bolt circle diameter 136mm with 8.0mm bolts.

[UNCIVILIZED]

Fill the old holes, & when installing the new winches drill the mounting holes for it a good distance apart from the old ones, preferably. Especially if it's easy to cover the old ones underneath with the backing plate so that they're not visible. Which, of course, try to use a substantial backing plate. Both in terms of size, & strength + stiffness.

However the reality is that a few small fastener holes are unlikely to weaken most fiberglass laminates much, if at all, measurably. Assuming that things were well built to begin with, & that's sort of a given if the boat's old enough to have been fitted out with Barient's from the factory.

Note that if you want to go semi-OCD about this, you can bond the backing plate to the underside of the deck. And also tap it for the fasteners, along with using nuts & washers.