This is typical for Majordomo. If you're aware of how to run a mailingIt's really easy: Don't use Majordomo :)
list the size of this one using Majordomo without such delays, I'd
like to have that information myself. (Though I'd say dropping
Majordomo for Mailman would be an even better idea)
This one's not very big. So you can do fine with Majordomo 1.94.x if you use an MTA configured to run a reasonably wide envelope split. All modern MTAs can be.
(However, Majordomo 2 would be a good answer as well, and it's much more configurable and powerful that Mailman. The web interface is daunting at best, but building a decent one shouldn't be a big challenge.)