A good rule of thumb: one host per five to ten VIP guests. That ratio gives hosts enough room for personal attention without becoming overwhelming. For larger events with many VIP guests you also need a coordinator. They direct the hosts and keep oversight of the full VIP experience.
Pick hosts who know the programme and get to know the guests well through the profiles. Give them the authority to make decisions on the spot. Nothing is more annoying for a VIP guest than a host who keeps having to check in for every small request. Give your hosts the trust and the room to act themselves within agreed limits.