Upgrading MU 2.9.2 with multi-db 2.9.2 -> WPMS 3.0.3

I have a wordpress MU 2.9.2 with multi-db 2.9.2 with 16 databases.

What is the proper upgrade procedure/path?

Upgrade multi-db to latest first, and then upgrade wordpress to 3.0.3?

Or upgrade wordpress to 3.0.3 and then upgrade multi-db to latest?