G'day Rosc0, honestly mate just get out there and have a crack at it. Sliders really aren't the most complicated things to build. There are a few things to take into account tho.
Here's a few pics of one we built for wakeboarding a couple of summers ago. I'm only just learning to kite really so wont be going anywhere near sliders with a kite attached for a while but it gives you a bit of an idea.
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Our main thing was that it had to be floating and portable because here in perth they're pretty strict on anything set up in the water as being a "boating hazard".
But yeh it worked really well, only took a couple of weeks of mucking around after work to get it together and with a few of the boys "borrowing" the materials from work didn't cost a fortune either. I've got heaps more sort of in-progress shots of the build if you want pm me and I'll email them through.
Cheers
Ved