Re: [460] "Ground Tow BASE jump"
Me and my pilot friends used to do these at night down the runway at the airport in Boulder. We used a BASE canopy and poly line instead of the normal paraglider and payout spectra. 600', then 1000', then 2000' of line. My paragliding vario once read 1600' AGL. Once you get the launch down, and the driver can 'feel' the tension or see a load cell and the pilot is not an idiot it gets 'almost' routine. Before my time a jumper here in Co watched his girlfriend die doing this "parascending" (just muppeteering the parasail thing, not cutting away). it's not "safe" but if you are not an idiot you can get away with it for a while.
One no-no we figured out was using the chest strap and handle release. Meaning just tying to the chest strap with a riser 3-ring is a muppet move. We used drop-releases (SUPER nice for this kind of thing. Makes it A LOT safer). We connected tow line to the chest rings or below the big ring in the slot, it makes all the load vectors line up instead of trying to tear the chest strap and squeeze the harness. Best of luck to you all though. It looks like you guys got it working pretty well.