The waiting time usually depends on the paint system you're using. Although they may be similar each paint manufacturer has specific recommended times between spraying the sealer and paint. Some may be wet on wet which means very little wait time and others may need a minimum of an hour or so. Most will also have a window where you'll have to spray the color and if you wait too long you may have to scuff the surface before shooting the color.
The best thing you can do is get a copy of the "P" sheet (Product Data Sheet) for the paint and sealer you're using. That will give you a lot of information. Mixing ratios, spraying pressures, wait times, what primers are recommended, what sealers you can use, etc. Most of these are available on line from the paint manufacturer's web sites.
Here's an example of a "P" sheet for the paint system I'm currently using for my deuce. It provides all the information someone might need to correctly use this particular product. Remember each manufacturer and each type sealer will have slightly different directions and you need the specific "P" sheet for the product you're using.
Martin Senour Crossfire Sealer Product Data Sheet
Some of the pro painters can probably give you better info, but for a backyard painter having the specific directions for the product they're using is always the best way to go. Good luck.
The most important things you learn are those things you learn AFTER you know it all. -- Chip Foose