I don't know if this would work for what you're doing, but I've always been a fan of the "transparent" tour design, like what you see on some of Kink's tours for example. (Although you may have to choose "Full" on the page if your link leads one of their other tours.)
In that style, the tour and the members areas are the same. You don't have to work on selling what's in the members areas if you actually show them everything that's in the member's areas.
Now that kind of tour is best suited for sites which have big members areas. You don't want to use a transparent tour if it's going to make it look like there's not a lot of content there.
What most people in adult tour design seem to do is pick out the photos and videos they want to use, then come up with a layout they like, and lastly they add the amount of text that fits, often editing for space instead of effect.
Personally, I think that's a terribly bad idea.
Before the online days, my business focused on direct response marketing using text ads, display ads, actual mailings that used envelopes and stamps, etc. As creative director and lead copysmith, if someone ever started a new project with the images and the layout at my agency they'd almost certainly be let go. (Except in that very, very rare case where the layout/image
is the message.)
So if you don't use a transparent tour, my advice is to sit down and write your tour as if you don't have access to any photos or videos at all. Write like your words are your only chance in the world to convey to your readers what they'll find inside the magic box. Write copy that spans from the warning text all the way to the final punctuation on the join page.
Then, when you've written and written, and edited and rewritten some work, and you're satisfied that your words alone can now do the entire job...then and only then can you make a list of the *kinds* of images and videos that are *needed* to help illustrate and emphasize the most important points you're making in your copy.
Notice I didn't say you should actually pick the images. No, at this stage you're only listing the kinds of images/video clips you
wish you had.
Maybe you'll find those images/clips when you go through the best selection of your content. Or maybe you'll have to choose the closest possible to what you wish you had. But the first task is always to make that list of the images/clips that, if you have them, will perfectly illustrate the excellent points made in your "could stand alone if it had to" copy.
Also...notice I emphasized the word 'needed' too. Extraneous images dilute the effectiveness of good copy, so you only want to use what are actually
needed to make your points. And when you make a point, stop. Don't dilute. Don't distract.
Once you've perfected your copy and selected
only the perfect images/clips needed, it's finally time to work on a layout and design that compliments the work you've done. The design can be simple or complex, depending on what's needed. But one thing the design must do is allow the copy to flow naturally from segment to segment on a page, and from page to page on the tour.
Give your words room to breath, make the type large enough and use good line and word spacing. Use negative/white space to good effect. Don't jam words into places they don't fit. Don't ever edit your copy to fit. Design the page to fit your copy.
I think you can see how far that approach is from what a lot of people are doing in tour design these days. Probably hard to find tours where the copy is good enough to stand alone. And even good copy is often forced to fit into page designs that detract from its effectiveness.
Anyway, that's my 2 cents, spend it however you like.
P.S. Take this for what you will, but I think you'll find that appealing more to those who read versus those who only look at the visuals on a tour means you're ignoring many people who will never pay for porn anyway.
P.P.S. You may not want to hear this last part, but you also want to make sure your tour uses the latest responsive design techniques or you'll be pissing money away.