What is the water volume held in the thermoblock of the Breville Infuser?

I am asking this question because I would like to try Hoon's idea of using a variable electronic controller on the power cord to my Infuser. This will (theoretically) allow me to control brew pressure without opening the machine and doing the "dimmer mod". My current brew pressure with the cleaning disk inserted is around 14 bars (why oh why does Breville spec these machines so high???) and I would like to try to achieve a 9-10 bar extraction.

I understand the dimmer mod only affects the the vibratory pump while the variable controller affects the whole machine including the thermoblock. So my concern is, if the thermoblock contains less than 100% of the heated total shot volume, then the temperature of the shot water would be reduced towards the end of the shot.

My plan would be to reduce the current to the machine right when preinfusion ends.

Here is a link to the variable controller recommended by Hoon.
https://www.amazon.com/Electronic-Contr ... 07T9BLJ7L/

I know - I'm going down the rabbit hole. But isn't it fun...

Hey. These machines are pretty easy to open, so I'd suggest you could take the cover off and try isolate the pump and run your thermoblock till no more water comes out. Otherwise you could try putting some food coloring through, run it through till you see it coming out the group then flush it out a few times. You could also run the unit without the h2o tank attached, but this would give you a larger amount then you'd be looking for.
Probably not the best solutions for you, but you have caught my interest.
Here's a pic of an infuser I fixed so you can see what you'd be getting into.