I vaguely recall seeing that method somewhere too. Although the one or two that feel like they could be slightly concave aren't really that bad, a ball couldn't get stuck on them, so I will probably just play it safe and leave them coz its so minor. Plus if i eventually seal the playfield with some type of clear coat I would imagine that should help too.
I wonder if the inserts go milky or you get tiny airbubbles using that glue method?
