I’m thinking of adding a load of reverb and effects prior to the mix. Is that ok?

Ideally not. We ask that you please supply multi-track files dry, without reverb or effects. But, if you feel that a specific effect, processing or creative element (filter sweeps, delays etc.) is an integral part of the sound then please provide a clearly labelled ‘dry safety’ version of your track with-in your ‘Reference Audio Folder’ when you submit your project (Any audio in this folder won’t be counted as an additional track).