i might suggest, you hook your lanyard to one front D; this can take a lot of pressure off the hips, make sure it is above the block!
Are you using tree gaffs, or pole gaffs? Tree gaffs bite deepr and at better angle.
Try wide mouth hinge, DO NOT CROSS FACE CUTS! Eliminate some wood from sides (leave nice hinge at front), especially leathery bark, leave only enough holding wood to usher complete control,as fast as possible, you can always choose to slow saw down, but if there is too much wood fiber migh not be able to speed it up, give yourself this wide range of adjustment, by allowing speed, but not using it unless you need it. Minimize distance between pulley and 1st hitch on load. Walk back cut to point of failure, have groundies pull over the top with rope at high leverage, flexing hinge through range of facecut slowly (you can push from back) to flex hinge with more 'meat' guiding it over. Then run smoothly, not allowing to accelerate, but not holding back total weight either. Soon as it leaves the stump, i slap my hand down on top of stump for stability. Snub out resulting force into ground, or de-accelerate before. Sometimes we redirect line from pulley to a slightly lower , but high anchor, to take out load. This can give more sideways movement in low diameter or springy spars so is not always the best thing to do. Pre-tighten line before you start, this will help pull top over and take play out of machine, usherring more control over load, you can always give more slack if you need to, so pre-tighten; to have wide range of control, just like pre-cutting for greatest speed control.
Use all these things to slowly hand load off with less force into pre-tightened rig, with as lil'drop as possible and run to ground. Minimize the forces against you, while maximizing the forces on your side. Take all these things and use them on all rigs, to practice daily; they all apply; then have sharper skills, understanding and feel for these big tests of their assembly and orchestration.
-KC
P.S. AIM is AOL Insant Messenger for chat.