The others are right, it is hard to work with a round shiny ornament. Yes, they are fragile and breakable, for you will making them transporting them to the wedding, and for the guest trying to get them home. And yes, not everyone treasures objects with names and dates on it. And you will want to buy extra ones to practice with. And please, do not resort to painting the info on with glue, and applying glitter to that. Way too grade school.
Consider just buying a ornament without the dates and names. I bought a set of 3 silver plate hearts with ribbons on them for a very reasonable price, probably did not cost much more than the price you will pay for all the stencils and paint. Angels, stars, hearts, snowflakes, any symbol of Xmas would be appropriate. Bluebirds are the symbol of happiness, cardinals a symbol of a marriage, they mate for life, as do some other birds. Swans are a traditional wedding symbol, too. All available at Xmas for ornaments. And they are all on my tree, I collect ornaments.
A friend bought some clear craft glass ornaments, and pours paint in them and swirls it around. You could do that in your wedding colors. Stuffing some with glitter or confetti or tissue paper strips a good idea, and inexpensive.
I saw wedding cookie cutters given as a favor. might want to consider that. they can be hung on a tree as an ornament, too.