90gr GMX for deer

[Bassfish1952]

Yes

With a few caveats.

First off LR (Leverevolution) May or may not shoot well in your rifle with the bullets at hand.

Some powders just seem to be the pixie dust that allow small groups with a given bullet.

To help you visualize this Go to Nosler.com look at the load data for another caliber that they have data for. As of yet they do not have data for the 6mm ARC. Bear with me here. Nosler offers some neat info that is not offered in total elsewhere. They offer case fill percentage, most accurate charge weight tested & most accurate powder tested. Your results may or mayn't mimic there results.

Notice: with any caliber say 6.5 Creedmoor for example how diffrent powders are listed as more accurate for different weight bullets. Then notice how different charge weights offer top accuracy while one powder works well at upper velocity limit. Then another propellant offers best accuracy nearer the lower limit. Not exactly, always,  straightforward.

Sometimes there are combinations that just shoot great in most all rifles. 6mm ARC has had relatively little time to have brought this info to the top yet. been especially difficult with component shortages.

If it were me I would start off with what we call a ladder test. You somewhat express this is your intention.
Would a chronograph help? You bet.
Nessisary? Not exactly.
is there a learning curve to the chronograph? Absolutely.

given the expense of the all copper bullets I would start my learning curve to reloading with a less expensive bullet. say a smilar weight cup & core bullet. Ill choose a 90 gr ELDX. you may go a diffrent direction. Will the data you glean from this cup & core test translate directly to your all copper bullet? Not likely.

Ok we can do our ladder test with your powder & bullet that is very similar in weight.

I would load 1 round at the low end of the spectrum. Write the grain weight on the casing with a fine tip permanent marker. load another 1/2 grain heavier & lable with marker. Work your way up to the max load with the 1/2 grain increases.
goal will be to test for shift in point of impact & or change in velocity.

For testing point of impact your means of resting the rifle will need to be very steady in a repeatable fashion throuought the shot string. I am thinking a front bipod or bags. Rear of the rife will be steadied with a bag as well. With no chronograph involved I would fire one round & hopefully your impact is within a few inches if the point of aim. not sure about your range setup, though in my case I would go when not likely to be at all busy.

So my routine would set target at 100 yards,  fire 1st low charge round. Walk down range & lable that point of impact as 1. inspect case for primer forme & proceed to the next higher charge weight round. take your time 7 fire another very steady shot 7 mark this impact as no 2. Proceed in the same manner through all charge weights.

What you are looking for is charge weights that do not change point of impact much ac the charge weight steps up a half grain or down a half grain.

Question for yourself is are you steady enough that your results are not significantly impacted by shooter error?
As you reach the upper limit you may see flattened primers or difficult bolt lift. You may need to stop with increased charge weights if pressure signs are telling you to back off.

While Lever evolution offers the most potential velocity: LVR may or may not offer the accuracy you are hoping for. LVR has its place for sure, May or may not be with your GMX bullets in terms of long range accuracy. Some times it takes trying another propellant to find the magic pixie dust.

Personally, I did not hold out a great deal of hope for LVR under the longer 90 grain GMX or CX bullets as I expect the powder may be, too compressed at the upper charge limits. Additionally LVR is not very temp stable. Lesser temp stability has the potential to translate to a load shooting well at 40 degrees, though not shooting well at 90 degrees & over pressure at 90 degrees. 

Or, a load that shoots well at 90 degrees F may may or may not shoot well at 30 or 40 F are question marks I prefer to not need to worry about.

Been watching a lot of YouTube and as much as I can on the 6arc reloading and for now trying to learn from others. I will use an indoor 100yd range for zero and will for this testing . But I just shot at an outdoor range that had a lead sled type rest and am getting one of those before the choreograph . 
I have 150 of the GMX so if I can work up a hunting load with 50 I would have 5 or 6 years of hunting left with the remaining 100. I do have some 90gr CX, I know they are not the same but are listed together on Hornadys reloading app and will sooner or later be availabile so using a few of them as practice would seem to be a good idea.
The numbers I have working out of the Hornady app are 
29.5 gr at 2800fps at barrel and 2283fps at 250yds and over a 1000pounds of energy working up to a max of 32.3gr at 3050 barrel and 2255fps at 375yds and again over 1000 ponds of energy with 6 steps between the 2 
Thanks to both of you guys you have been a big help, I incorporate some of what both of you recommend it helps.

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One last thing for now.

If I set my target at 50yds instead of 100 would it make any real difference in overall results, Since I use smaller scopes 2x7 and 3x9 I normally check my zero at 50 before moving out to 100. It seems to remove some of the error ?