For me it varies according to the pen. how glossy I want the finish to get.
I actually use Hut Crystal Coat because I almost always use a CA Finish.
A couple of coats, or passes usualoly does it. at times I will give it a third attempt just out of sheer hope. I have used Sellawax and used two to three coats then as well. Mostly just keep going until I am satisfied it isn't helping anymore.