You ordered your barrel. This comment may be moot,but just for fun,lets talk about the 7-08 Christiansen Ridgeline.
Its Lightweight and you have it. You might ask your outfitter what he thinks.
I have a few points to offer.
1) Unclenick is a Man to pay attention to. I have no idea how many rounds you fire to determine "Its a 1/2 MOA rifle" Unclenick has models that show we can get nice 3 shot or 5 shot groups that can mislead us. Our magic :OOOO AHHH 1/2 MOA load is likely a nice random cluster. Same load,same rifle,same day shoot a 20 round group and you will get other nice little clusters in slightly different locations. Sample size.
2)Call me a heretic but up to a point,group size isn't everything. Lets talk about the difference between 1/2 MOA and 1 1/2 MOA . The 1/2 MOA on theory will place its POI within 1/4 in of POA (point of aim.) The 1 1/2 MOA rifle will be within 3/4 in. Difference? 1/2 in at 100 yds. Or,in theory 3 inches at 600 yds. Many other factors can make that much difference.
Yes! You need enough accuracy . But 1 lb rifle weight or 150 fps velocity might be a fair trade for a suspected 1/2 MOA accuracy.
My Nosler book shows RE=15 and RE=19 performing well with 140 gr BTs
But Varget,IMR 4350, IMR 4895,and others approach or exceed 2850 fps with the 26 in test barrel . The 25 fps per inch rule of thumb would suggest a 150 fps loss for a 20 in barrel. That MAY indicate near 2700 is a reasonable goal.(Or not!)
Its a boost from 2550. You can gain SOME and retain "pretty darn good" Accuracy.
3) We tend to focus on the 1% or 5% shot. The 600 yd shot. It may be your only shot! True. Talk to your outfitter. I used to think in terms of the 600 yd rifle. I built a 30-338 around the idea, 2900 fps with a 200 gr Accubond, Then with my 257 AI I made about a 450 yd shot on a Pronghorn. DRT. Neck shot. But I was aiming heart/lung. Some mystery thread of wind. No bragging shot. Ot was humbling.
I know, We have a lot of long range experts here. I had a lasered 1100 yd spot on the ranch I used to shoot. No bench,but a bipod . I shot a fair number of targets there. It was not unusual to place 5 that could all hit a gallon jug. (Win Model 70 Classic Laredo 7mm Rem, Leupold 4,5 to 14 Long Range) But IMO,thats not the same as hunting.
Ask your outfitter . Is a 600 yd rifle worth 2 or 3 lbs weight over a 450 yd rifle? I can't tell you. I bet the outfitters nightmare is a botched 600 yd shot.
You could work up a hi-vel accurate 7-08 load and take a back up rifle.