Exchange 2003 DCOM Configuration

I have a single Exchange 2003 SP1 server which, upon reboot, the Exchange Information Store and MTS Stacks services are not starting. The event viewer complains that DCOM was unable to start the server. I've spent considerable time working on this, and I'm certain it's a Launch Permissions thing.

My question is this: what are the recommended Launch Permissions for the MSEXCHANGEIS (application ID 9DA0E0EA-86CE-11D1-8699-00C04FB98036)? I tried setting the Launch Permissions to simply "Default", but that did not work. What did work was setting the Launch Permissions to Custom, and then setting the Everyone group. I kinda don't want to leave it this way, and a Google search on recommended Launch Permissions returns nothing.

I think I found a solution, but I would still like a recommendation if anyone can make one. I tried setting the Administrators group and SYSTEM account to the Launch Permissions list (an nothing else). It worked; the Exchange IS and MTA Stacks service started up on reboot.

Like I said, if anyone can provide input, I'm open for suggestions...