Really, you can't know when you are giving 'too much', and you shouldn't be worrying about the surfers that manage to jerk off to your free site.

Concentrate on your selling to those surfers.

Pretty much by definition, most surfers are "just looking" - your target is the surfer that is on the edge of the excitement&impulsebuy threshold.

I'm sure you've already heard that the content should be selected to appeal to and push the excitement threshold of your target - that is, you try to tell a story to your surfers brain that makes them WANT more of the story.

The nature of that story changes with the niche you are selling. If you are selling cum, for instance, you have to include cum in the story, even tho you might think you should withhold the cum to keep your surfer from jerking off to your content. Your target 'cum' surfer, in this case, has a higher excitement threshold for cum than say a muscle surfer, and if you don't show them some cum, the switch in their brain clicks to the "NO - this is shit" position, and they won't bother to visit the sponsor in an excited state.

But the key to freesite and gallery profits is the selling you do with your links to the sponsor and the support text and suggestions that you associate with those links.