XNR,
The EGPWS has that rule in it as an extra, but the caution has no altitude associated with it, since the actual contact point is 14.7 degrees just as the main gear, oleos fully extended, touches. I would imagine that Adelt might cut the angle a bit.
Note that check's comment on bending the tailcone is simply not true. If the aircraft has a very hard landing on the mains, it might show the hard landing by having a dimple on the underside of the tail cone due to the slight downward bending of the cone (not due to touching the ground).