FWIW When I bought my first tibloc I set up 3 different ropes off my house (I have a corner of my house that drops ~28') and I wanted to see how well it would work. 3 ropes: 10mm Mammut, 9.5mm Edelrid and some bulk 7mm line I use for runners. Carabiners were BD OvalWires. I had a 10mm attached as well as back up in the event of failure. Even if I decked, I'd land on a thick ivy slope so the damage to me would be minimal. I allowed ~8'-10' of slack on the Tibloc and essentially stood on the edge of the roof and jumped. BTW it was a Saturday afternoon and the Mirror Pond was tasty and probably had somehting to do with my motivation for even attemting all of this.
The Results: the 10mm and the 9.5mm held just fine. But the 7mm ripped the rope hard. It held before I decked, but it really ripped the sheath hard. I was expecting this because I think the limits on the Tibloc are about 8mm??
I also did the same "experiment" with my old ascenders and Gibbs ascenders. Not sure if it was because of the surface area involved, but these both worked marginally better than the Tibloc.
Anyway, this was far from scientific, and I couldn't give you any measurements (Kg) of force, but at the time I was really curious how this simple device would work.