NWslackline Guide to longline, Part 5: Walking 

+Greg Welsh It's possible. I've used the primitive method to set up lines around 45 meters, like 150 feet. Any longer and it honestly just becomes dangerous to de-tension. My advice, however, is to use the 2 biner method with a third and fourth to make a multiplier. Essentially, run the webbing under itsself in both biners, that way there are two breaks, for two biner method. It's more redundant than one friction break and the high tension in longer lines is such that that redundancy is important. For multiplier, clip third biner to anchor and girth hitch (or whatever) the next biner to the pull strand to make the multiplier. There are vids on that, it's rather simple to set up, hard to explain. BE CAREFUL when you de-tension it! When you un-do the first break (which is where the walking, non-tensioning part of the line is) it won't de-tension, like it normally does. The back break now holds all the tension. When it pops it POPS, so LET GO real quick and make sure there's no biners or anything attached to hit you. Maybe even running a re-direct would be a good call haven't experimented with that. Hope that all makes sense, feel free to respond if you have any questions and ill clarify.

At my level, current record is 17 meters, flip-flops make it impossible to take 2 steps