Mismatched Batch & BBT Sizes - Issues?

[Public_beer]

With the setup I'm working on, I'll be brewing 4bbl batches to begin with. Double brew days will allow me to fill 8bbl fermenters, so I've decided on an 8bbl brite tank for crashing and carbing. My question is regarding carbonation of smaller batches in the 8bbl brite. Aside from wasted CO2 in the headspace, am I going to run into problems doing 4bbl batches? What about smaller test batches of say 1.5 - 2 bbls? I though it might make sense to just naturally carb test batches in 1/2 bbls, as they will likely be served in the taproom, and not distributed. (where a tap account may not appreciate the extra yeast) Thoughts? What questions am I not asking here…..?

[Graydon]

You will be able to carbonate a 4 BBL batch, I used a 60 BBL bright for 30 BBL. As the liquid level approaches the level of the stone it becomes a waste of time.
I wouldn't bother using the 8 BBL bright with 2 BBL or less.

Graydon

[Kushal]

I've put 60bbl batches in my 180bbl bright. And 15bbls in my 60bbl.

Only big difference I've noticed is that the large amount of head space will keep carbonating the beer if you have the pressure to high. We usually pressurize to 15psi while packaging and lower the head pressure down to 10psi if the head space is 50% or more of the tank.