Yes, there are probably something better out there.
But no accuracy at all.. why do you think so? Physics doesn't care if it's ugly.
The principle behind this is not to measure the vacuum in kPa or any other scale.
The actual value is not interesting and would differ from most gauges.
This creation would only show the difference between the vacuum/pressure in the different bottles.
When its the same preassure in all cans, no fluid will flow from one to another anymore.
They are in fact very sensitive to pressure or suction. Maybe to sensitive.
If i blow air with my mouth into one of the hoses, I can have the end of the hose 3-4 inches away from my mouth and the levels change very rapid.
My bet is that this would not work so good because they are too sensitive compared to the height, so I will have to little time to adjust.
If and when a bottle goes empty, I need to bleed hoses on top before another try,
I have to wait a couple of more days for an order with silicon caps to plug the air induction system before i can start the engine so i have not tested it yet.