CCVM Reflux Coil Question

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I've almost done putting my 2" copper CCVM together and in service

came up against a couple questions

I see many ask about how high above the TEE to run the column, but to me, that depends wholy on the Reflux Coil (RC)

my RC is 3/8" ID CSST coil, 5 inches of a single wind coil from 60" CSST

my water is fairly constant at 6C from my basement tap

I realize you only needs to have the RC at the top of the vapour outlet (VO) to have 50% reflux and full vapour outflow to the Product Condenser (PC)

but the question comes in, "how far below the bottom of the VO does one need to have 100% reflux and totally cut off the VO?

Now, I also realize there are variables in each different still/setup, but on average, where is the consensus?

This makes a difference as to how far above the VO I run my column.

I'm looking for a ball park, so I can shorten my column. if I go a touch to low, I can always reduce the length of the RC tails.

my initial thoughts were, being a 5" coil, 2" VO, I'd need at least 5" to keep the coil in the column, but any extra would not be needed, and the tails would need to be at least 7" above the top of the coil so when completely below the VO, the tails would hold it there

But how much below the VO does the bottom of the RC need to be to guarantee 100 reflux?

if just below the VO, I would only need to have 5" column above and very short tails

had anyone got real experience with this?

DAD300?