I would imagine that the CA first advice is a result of observations.

If you install a screw into a small hole first, you are effectively squeezing the wood along the sides and at the same time burnishing it. This would make it more difficult for the CA to penetrate the wood itself or at the least making the penetration more superficial.

The uncompressed wood, might be more prone to soak up thin CA.


Whenever I'm working with screws going into soft balsa ( not ply ) I put CA on FIRST to assure maximum absorption.

With ply I do the exact opposite, putting in the screw first, backing it out then applying CA.