In reply to Franco cookson:
Everyone's being harsh one you now. Suffice it to say that acccording to the classical model impact forces have nothing to do with the absolute length of the fall, it's only the fall factor (out of the possible functions of the lengths) that counts. At the very least, if you are going to leap frog you should use an old short length of dynamic rope, or ideally one for those dedicated Lanyards Petzl make for Via Ferrata.
It sounds like a pain in the arse emergency only technique though.
I don't know if anyone's mentioned this yet, but rope soloing is a pain in the arse, and using `orthodox' devices, you can only use a minimum of 10 mm diameter ropes (even though a Gri-Gri would probably lock on thinner ones anyway, and you'll be using back up knots anyway won't you? I said won't you?!).
Hence the invention of the Shunt system that Franco's just thought of too late. You need to mount it upside down using a shoelace or bungee through the hole in the back. And it works like a dream, and you can use skinny ropes, and double ropes. It has been tested (by a mate, and by me but with a gri Gri back up on an ickle fall, and some knots). The downside is the failure mode of the shunt is that the housing opens up and presumably your rope(s) then flick out and you're not attached to them any more
. I dunno if the advantage of using 7.5 mm ropes or something takes the impact force below the `body weight and a bit' that shunts are rated to. Shunts also have a large collection of slippage scare stories (when top roping) attached to them, even though I thinik these all relate to funny angles (on and around up routes on vertical walls, they're fine IMHO). But it works so scarily well, I think you can even invert (becuase the device flips anyway when you fall on it) that I'd really love Petzl to build a bigger bomb proof version of a shunt whose housing's way stronger. In a shot they'd instantly create the best rope soloist on the market.