I'm pretty sure the steel is good for 2 kN/200kgs.... as long as my dodgy welding is ok, it'll hold it.
The ground that you screw it into?? yeah sure, that's where the uncertainty is. you could screw it into a bowl of cornflakes it wont hold shi.t. I'm sure there's some dirt doctors on this forum that might be able to help you out with ground conditions.
as for the concrete pulling out because of crossed lines/setup that wasn't correct? you can't put it back down and correct the setup prior to letting it go? like I said I'm new to the sport, but I've been able to tell pretty quickly when the line connections looks like shi.t. you put it back down and sort it out right?
Bloke on about learning to self launch and have the kite pivot on it's corner, I'll probably have to ruin a few before I get to that point. I had a lesson last week and seems like the kite will always want to skid some?