What type of conformal coating should be used if the board has “press fit” connectors to be pushed through the conformal coating?
The key is to choose a soft coating to enable ease of push-fit and avoid risk of damaging the connector. Acrylic materials are generally used by most people doing this kind of assembly, although some softer urethane coatings can work with a bit more effort, especially if the connector is fitted as soon as the material is touch dry. UV cure materials are generally pretty tough after UV curing and so are less suitable (in general) for this kind of assembly.