I mashed my couple of MO smashes at 158. I also use a higher attenuating yeast. You do need to take that into account. Just blanketly picking a mash temp isnt going to give you the results you desire without taking all the variables into account. Other variables might impact this as well, like length of rest time, etc. If you know your system you can probably hit it first or second attempt.
Both of my smashes were around 1.055-60 or so (IIRC) and both finshed around 1.012-4 with a high mash temp. They both had that signature MO flavor....pretty nice.
Kegged: Millenium Galaxy IPA, German Pilsner. Apricot Blonde Ale, ACE Witbier, ACE American Wheat.
Bottled: Smoked Red Rye, Old Tanglefoot Barleywine, Tripel, Dubbel, American Farmhouse Ale