If you're still in load developement 3 is plenty. That's all I use. Also, I use .3gr increments. ie - 45.0, 45.3, 45.6, 45.9 - and so on. I think we had a discussion on another page about increments to use. Smaller cases - smaller increment..... Bigger case - like a .270 or so and use 3/10th of a grain increments.

But, to answer your Q - I use 3 rounds per measured charge for my OCD tests. Works fine & if by chance you end up with a flyer or flinch, I'm sure you'll be able to tell if you're in an accuracy node or sweet spot or whatever you'd like to term it.
I think keeping the rifle locked in position is as important. You want your rifle as stable as possible to get the best idea of what each charge is doing. When you get in the groove, you'll know. You see a 3 hole cloverleaf or a raggedy hole, you jump up & do the "yes!" dance....
Standard procedure....
Good luck with it

Frank in Fla