Where's that? I used the + or - buttons, and sometimes it was a pain in the ass to get to an specific value. What monitor were you tuning?
Mitsubishi 2070SB, which is what I think you have as well?
AFAIK it works at least in FACTORY 1, FACTORY 2 or FACTORY 3 screens, not sure about others.
The workflow is like this:
You highlight (or rather "navigate to") some value, lets say BTCEN. Now you would normally press MINUS or PLUS and the value would change in a small increment (from AB to AD for example) and the OSD would completely hide. If you wanted to do another increment (from AD to AF for example) you would need to go back and do it again and repeat ad nauseam. Now the "trick" is to instead of PRESSING the button (minus or plus) you would HOLD it, for a rather long time. While holding it, the value will keep changing (albeit slowly) and the OSD will be hidden at the same time.
To give you an idea, going from 00 to FF could take maybe even a minute of holding the minus or plus button, the values change rather slowly.
You could even stop holding it, admire the result for a moment and then simply hold MINUS or PLUS again and it will start changing again without the need to pull up the OSD again.
To try it, simply navigate over BTCEN and then start holding PLUS button for at least 20 seconds and you will see the screen brightness changing during which the OSD remains hidden so it doesnt mess with your colorimeter readings.
Hope it is more clear now.
By the way, 2070SB has 2 holes on the left side, bottom area. These holes are access for HOR and VERT sharpness pots. You will need a very long and rather thin insulated flat-head screwdriver to get in there, and you will need to educate yourself on the safety when working around of upto I think 30kV (I am not the best person to give advice) as the monitor will be powered on.