I think allowing a belt full of Full Rejuvs fundamentally changes the format. It heavily favors ranged and caster builds that can disengage, heal to full repeatedly, and reset fights. The spirit of a one-item tournament seems more like testing what a single piece of gear enables, not what 16 Full Rejuvs enable. I'd vote either no belt at all, or belts are allowed but must remain empty.
But if you do have a belt on, that's your ONE piece of gear. Tough trade off, amirite?