So, as you've gathered, all the readings from the meter were okay - the three numbers are the decimal values and seem to line up with what you'd expect: .600 - .900, depending on the number of wraps.
When you get a reading that jumps around, the two most common reasons are loose connections and 'soft' shorts between the loops of the coil, particularly with (semi)spaced coils. The first issue should clear up by tightening the mounting screws, the second often stops with dry burning (which forms an insulating coating on the wire).
The RM3 is a great atty - you should be very happy with it, after you get used to building, squonking, and
vaping it (which should take, like, 3 hours max).
To get your squonk down pat, try removing the dt when you do it and peering into the dt hole. You'll be able to see the juice welling up and get a feel for how hard to squeeze to get your desired level. Others watch the air hole from the side - when you see the juice juuuuuust start to appear at the hole, you're good. Remember to let the juice sit at that level for a few seconds to let the wicks get saturated.