Thanks Jason. Primary fermentation was done in 6 vessels (4 glass carboys and 2 plastic primary buckets). The barrel is our long term secondary vessel.
Just topped it off with 5 gallons of the same recipe that we used WL Belgian Sour Mix as the primary yeast. Hadn't tried that before and if anyone's wondering, the apparent attenuation was good reasonable and we dropped almost all the way down in about 7 days. Normally we use this in the secondary (and did in the barrel). Thought that was interesting.
When we topped off, a pellicule was starting to form. Not sure what happens with that now that much of it is coming into contact directly with the oak now that the barrel is full.
If anyone sees any red-flags in the steps to-date, by all means we'd love to hear it. Fingers crossed to the extent that it might be beyond our control at this point!
On first sampling after topping off, so far so good. Now we wait until the beer tells us its ready