The coil on the spd8 has a different type of fraction collector design than previous models and if you dip the coil temp down it will act as a violent collection of molecules dragged to the coil like a magnet. That coil would inherently distribute those lower temps right on the surface of the fraction collector dish and that would display a whole new set of efficiency within the head.
The condenser in the head absorbs as much heat as possible and removes btu energy from the vapor prior to entering the condenser arm. This allows the vacuum jacketed head to operate like it’s supposed to. The coil in the head doesn’t disturb molecular flow dynamics as it’s duty is to absorb heat before the heat affects the sides of the walls of the fraction collector as well as allows those ambient vacuum void temps to be more stable. When you get blow by in a head it means it’s just working overtime because the arm sends back fluids to the heater chiller and it can’t maintain the btu heat removal. So if you can maintain exact temps you can bounce unwanted fractions right out of the condenser arm without over shooting flow rates. This maintains a drier vacuum in the condenser arm.
Included with this head: