Just a few comments first i,v tryed stopping the engine just as you come over the hedge and the prop will not untill the speed is down to about 25kts due to inertia and windmilling if your luck is in the prop may not strike the ground ,forget trying to crank it horizontal you have more important things to do in that 20 seconds.
I cannot see how the nose gear can retard the main gear once it is locked down ,the freefall for the PA28R gear works by releasing the hydrulic fluid from the UP side of the retraction jack and letting fluid into the down side side of the jack as the leggs start to drop they may be retarded by the high demand for fluid to the down side of the jack but this affects all the legs the reason for main legs not locking down after free fall is lack of bearing lubrication as i described in my last post on this subject.