Advice Wanted: Setting up fresh to brackish water

[Pamiam]

A week ago I bought 3 bumblebee gobys and 2 balloon Mollies. Of course, they were in a freshwater environment. I would like to start to acclimate them to brackish where they should be. Currently my specific gravity is 1.004. I am not sure what the end specific gravity should be, I have read up towards 1.010, others say lower.

If the specific gravity needs to go up, how long do I keep them at 1.004?

So far, all are healthy and eating well.

Any advice would be great, especially on the bumblee gobys care.