This is logistics, and it should be planned like logistics
A coach is what you book when the problem is not a celebration but a movement: two hundred wedding guests between hotels and a venue, a company moving staff to an offsite, a group needing to arrive somewhere together and on time. The useful questions are different from a limousine booking. How many people, from how many pickup points, arriving by when, and does the vehicle wait or come back. Answer those four and the plan builds itself; leave them open and the day runs late.
Guest shuttles are repeated runs, not one trip
A large wedding is rarely a single coach movement. It is usually several runs between hotels and the venue before the ceremony, then staged departures at the end of the night so two hundred people are not standing outside at midnight. The Four Seasons Westlake Village is the clearest local example - its Grand Ballroom seats up to about 996 for a reception, and a guest list at that scale is a shuttle problem rather than a limousine problem. Send the guest count, the hotels and the venue timings and reservations will come back with a plan rather than a rate.
Luggage bays, and what that lets you do
The underfloor bays are the practical difference between a coach and everything else in the fleet. They are what makes a coach viable for an airport group movement, a corporate offsite where everyone has an overnight bag, or a sports team with equipment. Send a luggage or equipment estimate alongside the passenger count - the vehicle that seats a group does not always carry the group plus their bags, and on a coach that question has a real answer rather than a hopeful one. It is the single detail most often left out of a first enquiry, and the one most likely to change the answer.