For the most part I'll take accuracy especially when your talking a difference like in your case. However when you say shoulder shots are what you want to take, then it factors in a bit more. I would personally lean to some more load development before hard fast choosing. The Shockwave with 85gr should get it done but I don't know as I have never used anything smaller than 240 on game in my 50 cal. I will tell you 250 SST(or Shockwave) will as I took a large bodied buck through the shoulder and exited clean with no further steps last fall, that was with 100 gr of T7 loose....but a hunting partner took buck through a shoulder shot using 250gr SST with 100 gr pellet T7 with similar results.

I am not an expert by no means, just a hunter. I always look to find the best for my hunting needs be it energy, trajectory, accuracy, setting forth personal limits and many cases all of the above to ensure my main reason for blowing smoke is a smile at the end of the season!

Best of luck