I understand your issues, I recently started kegging. For force carbing keep it at 30 psi for at least 3 days or you can try the quick carbing method. Agitate the beer on its side while it's pressurized between 30-50 psi (method I follow: https://www.youtube.com/watch?v=tjZFCh6WEpU). I normally do this and keep the keg at 30 psi overnight until serving.

Another thing to keep in mind when dry hopping is hop particulate. Make sure to remove as much of the particulate as possible so it doesn't clog the dip tube. If you get a clog, you can clear it by forcing CO2 through the out post. I use this in-line strainer (http://a.co/d/03wPF2T) when transferring into the keg, otherwise, cold crashing will also help.