This is somewhat of a trick question because volume of alcohol is dependant on how well your wash ferments, and how much alcohol is present in that wash. Think of it like this, the newer reflux style stills (Turbo 500 & Essencia Express Stills) will produce a higher strength finished product. If you were to collect 3.5 litres using a super reflux still at say 80% or the same 3.5 litres of alcohol using a Turbo 500 at say 90%, then once you have watered both down to 40% the Turbo 500 should give you a higher volume of finished product. That being said you would have had to have collected the same amount from both stills for this theory to be relevant.
All stills collect alcohol from your wash at varying strengths, but at the end of the day though, the total amount of alcohol collected is dependent on how much is present in your wash. Newer Reflux Stills collect alcohol at a much higher strength than the previous model stills were able to, so in reality even if you are not getting more alcohol, you are in fact getting a cleaner and better quality alcohol!
Another advantage of newer stills is they have a considerably shorter run time than the older reflux/super reflux style stills, usually finishing in 3.5-4 hours as opposed to the older models 6-7 hours!
Alcohol should always be watered down to below 55%/V before filtering, as carbon physically cannot treat alcohol at higher strengths.