Sidur Kedushin is generally considered the most prestigious Kibud given out under the Chupah. Since the Mesader Kedushin is Motzi the Choson with the Bracha, the Choson should choose the person he wants. However says Rav Moshe Shternbuch (2:672) the minhag is that if the Kallah’s side pays for the entire wedding they can choose, unless they pass the honor to the Choson. If the Choson’s side pays part of the wedding expenses than the custom is that the honor of choosing goes to him.
Rav Shternbuch adds that nevertheless the minhag of giving it to the Rosh Yeshiva of the Choson is not correct. It is Bitul Torah to make the Rosh Yeshiva come for this kibud. There is no special significance to siddur kedushim unlike being Sandak at a Bris which indeed is a very big kibud. He says that traditionally it was always customary to give it to the Rav of the city or community, and pay him for it. In fact he says the Tchebiner Rav would only come to a wedding on the condition that he would not be Mesader Kedushin and the local Rav would receive the Kibud. Revach
The briskers have it much better! By them the biggest kibud is being an eid and therefore each side can pick one!
If the Chosan and Kallah can’t figure this out together they should not get married. There are significantly more important issues that come up in life.
#2 – a lot of times it is the parents not the chosson and kallah
Very original name.