I like your off-camera flash technique, but a few things that the photographer should know and be prepared to guide subjects with are:

1) Which side of the jacket the boutonniere should be worn. On their first dance it will be trashed, plus it is in the face of his date.

2) On a two button jacket the lower button is left open.

3) For action shots the jacket should be left open . . . casual.

4) In general, if possible, the lady should be on the gentlemen's left. One exception is when walking down a sidewalk next to a roadway the gentleman is always on the outside, next to the roadway.
The lady being on the gentleman's left is a tradition that began when gentlemen carried swords and had to have their right hand free to draw their sword to protect their lady. (I guess another exception here would be if the gentleman was left handed)

Who said event photography is easy?