flute/plated column question.

[ohyeahyeah]

I notice when researching plated columns that some Carl stills sometimes mount the column right on the boiler like a regular flute build while other times use a swan neck or straight copper head with site glass and then run an output to the bottom of the column which is running parrell next to the boiler. I get that they build to customer spec.
My question would be does anyone know if the swan neck with the site glass have a bubble plate in it? Either way is there any advantage to this? Seems like it would take more heat to run it side mounted as you would be getting less heat in your column through conduction.
What could be the advantages to the "bubble ball" as opposed to just adding another plate to the column itself?
Im building a 4" stainless flute with all copper internals based on OD's second build with the 2" bubble caps.