Thanks @arnathor and @selvedge8tweed
Mazz shirt collar stays up well without jacket. I am traveling and will probably wear the shirt again, so will snap a pic for you.
Jacket: LBM 1911
Belt: Farnese (via NoManWalksAlone)
Shoes: Car Shoe
Bag: Chapman (via NoManWalksAlone)
Cheer on the collar. If you do have a pic, please post. But I'm guessing that given the smaller collar, it stays up better than a spread collar. It would be nice to have a non BD alternative for casual shirts.