No such thing as partial conceal. It would be under the brandishing law, which in your case, doesnt seem like it would apply, a holster is a holster. No where in the Michigan law does it state what type of holster you have to use for open carry, it just says in plain view, in a holster.
IWB or OWB types do not matter....Cant stress that enough. Ive used both to openly carry, never had any type of problems. I would take that to civil court against the PD, possibly win some money, and for sure have it wiped off your record, just got to find an attorney to represent such a case whos also experienced in such cases.
Only two defining forces have ever offered to die for you, Jesus Christ and the American Soldier....One died for your soul; the other for your freedom.