I thought that when I read the original post that you got your schematics from, the author had specified using both a digital and analog meter.
One for one setting, one for the other.
IIRC the use of the el-cheapo analog meter was to see how smoothly the needle sweeped, this would show any dead spots between the wiper and the bands on the potentiometer (TPS) that is being tuned. This would be hard to see with a digital MM only.
Kinda' along the same lines as the old needle tachs. being more easy to read than the new Digital Tach. on the MFD's that roll numbers by so fast, it is hard to read where your at.
Thoughts?