Getting back into the shop after a too long hiatus (Partly while building the shop ...)

I'm prepping barrels for rust blueing, and I've got a few questions about managing the water exposure:

Primarily, I'm wondering how to keep water out of the rib space? The front bead hole and a weep hole (not sure what it's actually called) both seem to communicate with the space between the barrels. (Pics)

I'm also interested in what you all think about plugging the barrels vs leaving the open for the boiling?


[Linked Image from i.ibb.co]
[Linked Image from i.ibb.co]

Jim