How much time between spraying the primer, and then spraying the gloss coat?

Using any type of paint, there is a big difference between dry, and cured. While some paints may be dry to the touch in just minutes, something like a lacquer or acrylic usually needs about 24hrs to fully cure.

Enamels take longer, could be anywhere from a day to a week, sometimes a month or more, just depends on the paint. Easiest way to tell is to give it the sniff test. If you put the kit up to your nose and still smell fresh paint, then it isn't cured, and is still "gassing" out. Trapping that process under another coat of paint, or varnish coat will lead to some problems.

As far as glue lifting the paint....just part of the process, as the glue will eat into the paint. You are much better off gently scrapping away the paint where the part is going onto, thus giving it a plastic to plastic bond, which will not only save your paint, but will also create a much stronger bond of the parts because basically the part is only being adhered to the layer of paint, and not the actual plastic, and the glue being much stronger will weaken the bond the paint has to the kit, and off pops the part.