while the hole at CHF may seem bigger than the hole at CHB, i feel that the other young tall options, in vickery, elton and astbury offer more up forward than down back.
a good CHB can really control a game. A bloke who can provide a marking option from the kick out and then be able to hit up a leading CHF is worth their weight in gold, and can make your forwards look good. CHB was often referred to as the pivot.