What a speedy reply!
Don't need to know where Franc learned to be a tailor but his occupation is useful information. He probably continued to be a tailor when he got to the US as that was a good trade to have.
If you cannot find exact date of birth, just get as close as possible. If the church has the names of the parents, be sure to get that information also. It was quite common to name your children after your parents.
When I did a search for Vucajnk on Ancestry.com, a lot of variations came up but only 5 with the exact spelling came up in the US. They were all for NY passenger immigration records, which I don't have access to, but none of the first names were even close to Franc or Ivan.
I would guess when the Vucajnk's sent packages back to home they would have used the "old" spelling of the name so that everyone would know who they were; that's what I'd do.
Maybe another poster would know what Vucajnk might have been changed to. Immigrants seemed to change their last name to match the pronounciation. Since I cannot pronounce Vucajnk I don't have a clue.
Just because I'm big into genealogy & a curious person, what nationality is Vucajnk? Looks Hungarian to my untrained eye. My grandma was Hungarian & I can barely pronounce her maiden name [Doszpoly], lol. I'm only 95% sure that's the correct spelling as she spelled it several different ways.....she was a child when she came to the US.
You can email me direct if you'd like when you get further information. If you send an email please write something in the subject line about genealogy so I'll know it's not junk mail & don't delete it in error.