How do you communicate what rules you're using to your players?

So, the whole big trick to using GURPS successfully is to ruthlessly cut down the rules you're using to just the ones that are useful to your campaign, right? So how are the rest of you sharing with your players which rules apply in a given game? Or do you share them at all? I'm running a game right now which has taken a "generic" Dungeon Fantasy world with all the races and magic options and everything, run it forward a few hundred years with generally low mana, low sanctity, etc; and advanced technology up to a steampunk style setting. I'm running it as a high adventure campaign, so some Action components are in, and we've got automatons and artificers and such, so weird science and metatronic generators are included. And since the players are managing an airship that's perpetually about to go broke, I'm looking to the After the End scrounging and invention rules. I've also supplemented all this with various other Pyramid articles.

So I've got around a dozen or so rules sources, on top of the Basic Set. Now, I knew when I was setting this up that there'd be a lot of splicing sources together (that's part of the fun!); but I didn't think through how tricky this would be for my players to work out. Right now I've got versions of the PDFs edited down to just the salient details, but I'd love a better way to present a cleaner, unified ruleset for them. Has anyone else run into this? Or have you found it best to just hide the sausage making from them?