Brother of The Benz, Alon
If it wasn't that my W124030 has an Eco Gauge, I would install an attractive Stewart Warner Motor Minder Vacuum Gauge.
It would tell me more about the condition of my engine than the rinky dink gauge I have.
I may get one anyway now that the subject has come forward.
Alon, don't wish for something that is just a indicator of your throttle position.
Get a Good Gauge and thumb your nose at we who have the M/B thing.
As for the position of the needle at idle in gear, to the left. Not as when in nuetral. When cruising, to the left. Underload, to the right.
Happy Trails Beep Beep from The Spiderman in Houston!!!