Questions on bullets and powder

[A5BLASTER]

I finally got everything set up and loaded my first 25 rounds today. To recap, I?m using Hornady virgin brass, WSR primer, and CFE 223. I started with 29.7gr up to 31.7gr in .5gr increments. 5 rounds per weight.
Nosler doesn?t have load data for that bullet so I used the Hornady manual. I don?t have a headspace gage or an O.A.L. gage so I was unsure about COL.
What I did was measure a factory round that shoots pretty good in my gun. The 123gr ELD-M Hornady Black measures the ogive at 1.657 in my comparator. So I set my seating die to replicate this.
So, my OAL is 2.186. Was this a rational starting point until I get the additional tools I need?

That coal of 2.186 is short. And it's not really safe to work up 5 tenth increments in the grendel case.

Better to do 3 or 2 tenth increase when working up.