Liturgy Bleg

A good friend of mine who is getting married this summer (they're a lovely couple!) asked me to do some research on the Catholic custom of the priest wrapping his stole around the couples' joined hands during the wedding ceremony. I've found references to it in Fortescue's Ceremonies of the Roman Rite Described, which notes the custom was first mentioned in print only in the 1954 Collectio Rituum, and in no other texts, despite being customary in some places. The nuptial mass will be a Missa Normativa, but the happy couple wants to introduce this lovely custom into the rite.

My questions are 1) is there anything which allows adaptations like this into the marriage rite in the U.S.? I am aware of a directory of ethnic liturgical practices (such as the Ukranian crowning ritual) which are permitted to be introduced into the Latin Rite marriage ceremony in Canada, but I don't know how similar cases are relevant here. 2) Because it was so lately codified and apparently never suppressed, perhaps due to a felicitous oversight (it is simply not mentioned in the 1965 Roman Ritual), does the law of custom allow it to be included? 3) Can anyone pass any other references to this ceremony on to me?