You can lower the low kite until it is on the same level as the glider. (or even lower. But maybe the lines hit the wings of the glider then) In that way you can also control the amount of lift the glider gets and therefore the height. This can not be done by the high kite otherwise the diffence in windspeed between the two kites gets less.

I think it is at first only suitable for speedsailing and as a stunt just to show it can be done. Maybe as control gets better it can be used for recreation. For transport it is not suitable. The kites need to be too big. You depend to much on the weather, it is relatively expensive. And you can't carry much. It has to be tested rc very thoroughly at first. Kites are not always stable in variable winds (lower kite). Maybe the wing of the monofoil is needed. This wing ajusts automatically and very fats to windshifts and variation and is therefore very stable. But then you need a quite complicated machine. But again it is not impossible

I also haven't found back data on SKYSAIL yet but I'm working on it.

I'll make some drawings and send them to you.

Regards,

Johan