In reply to Eric the Red:
My measly 10.5 stone gets very easily suffocated and virtually dislocates its back just trying to hold a pre-planned below-me fall when practising SRT with my 13.5 stone partner.
And as for how I attach to an anchor point, I certainly want to be comfortable and able to move around and stand how I wnat, shift position, etc - so I'd recommend anything that allows that, subject to preferably attaching to the belay loop or rope loop itself rather than the harness.
But what about dynamic belaying? I hear that it's becoming more the thing to allow the belayer to move somewhat (i.e. leave the ground) if a fall happens so that they absorb some of the strain of the fall (see recent Summit article on fall factors/forces on gear).
Someone fairly experienced/knowledgeable told me recently that there were now ideas being mooted about having a very slack anchor tie-in (i.e. a long and loose slack sling) for the belay attachment, rather than the older-style idea about it having to be tight (assuming siad anchor is bomber, I assume...)