New modula column build

[Royalwulf]

I am building a modula column still. I read the page "Calculations for a Reflux Still"
The page said:
"Understanding the flowrate of distillate you are collecting, you can determine the reflux ratio that you are getting from your cooling coils etc. Once you know this, you can work out the HETP for your packing, and thus the number of "theoretical plates" your still has. This will determine the maximum purity that you can achieve "
Can someone give me more information or send me a link to more info on this?
I know how to measure distillate flow rate, but given that how do I determine reflux ratio, HETP of my packing (rather than theoretical), number of "theoretical plates" and maximum purity?