For the best results, 20-30 minutes is recommended between each coat of tape. For most applications, 2-3 layers of tape is recommended. After the multiple coats of tape have been applied, it will normally take 24 hours for the tape to fully cure.
Gardner Bender FAQ
Gardner Bender's frequently asked questions.
Gardner Bender FAQ 
For best results, do you recommend adding multiple layers vs. applying an initial thick layer? Or doesn’t matter?
It would be best to apply multiple coats, that way each layer can be allowed to dry. With a thicker single coat it is harder to judge if it has dried or not.