I get 2630 fps with 175 FGMM out of my 23" 1:10 twist AX308 barrel, suppressed, at about 50-60F for ambient temperature.
I think you'll be close with your prediction of 2580 fps. If I was you, I'd look at the data for 2550, 2575, 2600, 2625 fps, and look at what the changes are at the ranges you'll be shooting at. That's what I like to do - if I know my velocity is 2600 fps I'll make a +/- 25 fps card, along with a 2600 fps +/- 2000' DA card. Then I'll be covered enough if I think I'm gaining/losing speed, or if the DA is 1000' in the morning and 3000' in the afternoon.
That being said, I generally rely on a non-AB Kestrel and Trasol on my phone, but should my phone go down at a match I like to have data cards as backup.