I've watched Kurt's restraint system, and the other guys that use it. These work pretty well. There are only two drawbacks; One - you must be able to drive it into the earth/surface. Two - it transfers the FULL forward-pulling load to the leading edges of the stabs.
Airplanes with removable stabs and stab-tubes get a LOT of stress this way, and I've seen lots of structural wear from the nylon ropes/straps/webbing.

Another system that works is a "shear pin" restraint, where a "push pin" is inserted into a tube crossways in the fuse, usually installed at a junction of vertical side/formers/bulkhead, such that the "load" from the pin is distributed on the sides of the fuse/plywood internal crutch.

Works very well, if you remember to loop the rope from the pin over the stake (forgot that once and got a belly full of an Ultimate with a 3.0 Fuji at full throttle. Wasn't pretty.)

Pics attached of 30% Yak restraint. Pin example (there are MANY like it) from McMaster Carr.