D - reading your initial post, it is my experience that no ML bullet is going to immediately kill either of these deer. The possible gut shot one yes, in time. But the first one may go on indefinately. Whitetails are tenacious animals and even a one lung hit deer can travel a long way. Like in archery, when in doubt, back out.
If your SWs are producing good accuracy, there is no need to change. But YOU need to practice some dicipline and take good shots.
Now I'm not saying the standing still broadside shots you always see on TV. yeah, they are ideal, but slowly walking broadside or qtr. away, certainly.
Honestly, if I had to wait for a standing broadside shot, I would not have taken 30% of the deer I have shot. Good luck