On One Pompino owners...

... Sugino RD messengers, and I've read they go with a 103mm BB. Is that it? Or do I need to start worrying about my hub and it's measurements?

The 103mm BB length for the messengers will be associated with a partciular chainline (typically 42mm for fixed hubs). You need to match the chainline at the cranks with the chainline at the hub....

For some unknown reason* even with a 103mm BB you have to run the chainring on the inside for the messengers to get a 42mm chainline. From memory the outside gives 45mm. Most track hubs give a 42mm chainline.

Sheldon is good. You should also look in mech & fixing on here. There is a sticky for good websites.

*probably because they're just road cranks.