I finally got some VR Optician inserts for my Quest, so quick review.
Overall pretty OK. They protrude very far and put pressure on the bridge of my nose, even when using the glasses spacer. The lenses themselves curve inwards, so the adapter is probably built to accommodate the thicker lenses of stronger prescriptions. Clearance issues can be mitigated by moving headset away from sweetspot, but that obviously isn't ideal. 
Overall I guess I'll be using them, but might have to add some padding so they stab my face less.