I'm not so sure about the LeverEvolution ammo. Their performance gains are really deceptive advertising. Every other ammo maker shows 30-30 ballistics with a 100 yard zero from a 20" barrel.
Hornady uses a 24" barrel to boost velocity and they don't tell us at what range they have it zeroed. Only that it is 3" high at 100 yards and is still hitting high at 200. Their zero is somewhere between 225 and 250 yards. This makes their ammo look pretty good at 300 yards. Zeroing a 30-30 at 250 yards is a good way to shoot over a deer or bear at 50 yards where most of your shots will be anyway.
Take any other 30-30 ammo, shoot it from a 24" barrel and zero it at 250 yards and the drop at 300 will be VERY close.
I just ran the numbers A conventional 30-30 bullet with a 250 yard zero has 3" LESS drop at 300 yards than the LeverEvolution ammo. With a 225 yard zero the LeverEvolution ammo only beats it by 1.5".
With the ammo choices you have it is a toss up. Either will work fine, but I'd still go with the 308. With better, heavier bullets the 308 will be much more effective on larger bear or at greater distances.