I have hunted mule deer with the .357 and I would suggest stickink with an expanding 158 gn. with the longer barrel you will increase the range at which they will expand well and the wieght is a big help in penetration.
Bear in mind that I have put a 150 gn .308 through, in and out, a blacktail at 25 yds, 0 expansion and the energy went into a hillside, but the deer dropped in it's tracks. It was all about placement.
Practice untill you can keep every shot on a paper plate at 75 yds from a field position and then try to limit yourself to 50 yds for real.
"Oh bother" said Pooh, as he punched the magazine release...
In some peoples minds "What if?" is just as real as What Is.
Think good thoughts about Ronny moving to the Netherlands ASAP