I'll take the higher SD. Thing about relying on the new designs is you have to be careful to account for instances when they fail. High SD is insurance. Of course, if you get heavy enough you find that cannon balls are effective. So, there's that.
For recoil sensitive shooters on game on open ground, I'd go for a 120gr 6.5mm or 130gr .277 of monolithic design. Penetration is assured, and if it fails to open it's not such a big deal out in the open.
If you might get by with something with more recoil, it is important to consider that a heavier bullet will be easier to push to a given velocity in a larger caliber. If you're going to use a 150gr, use it in the .308, not the 7mm08. The 7mm08 is for 140gr and so on down the scale.
If you will handload, and have not bought the rifle, consider a 270 WSM with reduced loads to start.
