Setting up a 3750 as an mrouter

[professorguy]

I have a few multicast sources and clients sprinkled around the campus. I have Cisco switches (2950s & 3550s) for access all talking to the core 3750 stack.

The IGMP snooping is enabled (this is the default) on all the access switches. No switch has been designated as the multicast router (mrouter). A 'show ip igmp mrouter' shows no record on every switch.

Two questions:

1) If I put all the various sources/clients on the same VLAN will this work without an mrouter? When a snooping switch sees a multicast packet, but can't get it to an mrouter, its fallback is to flood the VLAN. So this would work albeit inefficiently.

2) If I make the core stack into the mrouter, will all the switches suddenly know (just from the 60 second updates) to trunk the multicast packets to it?

3) If I change from a switched to a routed network (my ultimate goal), what will have to be done to keep the multicast working? How will the multicast address get routed when one router has a trunk to 192.168.11.0/24 is it still going to be smart enough to also send 224.0.0.0/24 traffic as well?

Thanks for any insight.