x-post Invitation Wording- Church

I thought I decided on wording, but the more research I do the more confused I am getting.

My original (we are hosting):
Request the honor of your presence
at their marriage

Now I read the honor should be spelled honour since it is a house of worship.
Also, we are doing a full mass, not crazy about Nuptial Mass but how does this sound:

Request the honour of your presence
as we unite in the Sacrament of Holy Matrimony

or
Request the honour of your presence
at the Nuptial Mass uniting them
in the Sacrament of Holy Matrimony

Any thoughts or suggestions? What you are doing?

I am also doing a full mass. My invitation says
Mr.and Mrs. -----
and
Mr. and Mrs. -----
request the honour of your presence
at the marriage of their children

Out of your two choices I like the first better.