I am a complete newbie to this. After some frustration getting my pro 1000 set up

I have started dropping powder ..... I am making 9mm ammunition using 115 grain bullets and Winchester 231 powder. Weighing on a Cabela xt 1500 scale. The modern reloading book says 4.3 minimum grains and 4.8 max.
Using the .40 powder disc it drops an average (30 loads) of 4.2 grains. min 4.1 and max of 4.2?
The .43 disc throws an average (15) of 4.52 grains, min 4.4 (1) max 4.6 ??
Now they say start with the minimum and work up. Using the .43 I'd be at in the middle which is in the safe area.
Do I open up the .40 (drill/sandpaper) so it throws a little more powder?? Or just make ammunition using the avg of 4.52) and shut up!!
Steve