I am suspecting they might not be the correct glasses at all
What shape and size are you looking for?
I do trawl my local charity shops, sets of small shot glasses do appear. I missed a lovely one with different Spaniels on it a few weeks ago. I'd "noted", went to pick something else up to look at it - and in the few seconds interval, somebody else grabbed it.
However, I shall start looking for you.
(I wouldn't normally bother paying attention to things with horses on.)
I know exactly the sort of scenario you are describing!
My Grandpa used to prepare cocktails for everybody just before Saturday and Sunday family lunch.
He had special glasses and a special individual "recipe" for each person.
He would have them all mixed and lined up on top of his bookshelf, for folk to take while waiting for the roast to rest before serving.
I used to get the job of pouring out the wine at table. This meant I could ensure there was a little left in the bottle - which I got.
There was method and motivation behind that.
(Gripe water was alcoholic in those days - I'd regularly pretend to have a sore tummy to get the booze when I was a child.)