I'm not really a fan of those red cones, after using one a few times. The tongue moves in an arc rather than a line when jacked, which means it moves forwards and backwards a little. You've avoided the problem by having a relatively slick block under it, but fixing that means the chance that the cone will tip/buckle instead.
Personally I like the rigid "foot" type that attaches to the bottom with a pin. That way it can slide around a little and not have any chance of buckling or falling.