I've done multiple brake fluid flushes on the 997 and every time I just sort of wing it.

Does anyone know the exactly or approximately how much fluid is in each line?

 

What importance does that make?

When switching fluid, use a different color: Go from Blue to Yellow and back.
In addition you will need at least 1 liter to completely flush the system and more if you intend to be really picky and **** about it.
Once a bottle of fluid has been opened, you cannot keep it for too long as it will suck all the moisture in the atmosphere.
Of course, you will want to use a single-person pressure flush system (about $79.00).

Yves

 

1.) I use SRF
2.) Blue isn't sold anymore (ATE 200), colors are out
3.) I think you can flush using less than a liter.
4.) Saving a little let's me retain some so when I bleed, I can add a little to the reservoir without opening a new bottle.
5.) I will bleed the calipers 3 times this month
6.) Knowing the measurement takes the guess work out, I can just put marks on my garbage bottle, when it hits the line, close the valve and move on.