External down-comer?

[Manback]

So, before I start on my 3" bubble cap build I wanted to try modifying VM/LM column to use a bubble plate take-off. The easiest way to do this would be to have the down-comer as external. I thought the excessive cooling might be a problem but the no-return will only hold 4-5mL tops, so it'll be getting returned pretty quick, and it's SS not copper.

Anyone see any potential issues with doing it that way?


EDIT: Busted up a (super-rough ) diagram, to make things clearer if I wasn't in my post