Can I suggest that you have a look at my website
www.carpathinreflections.com? The Main database indicates where you might find bdm records. The subdatabase page has many names found in correspondence transcribed. An ongoing project is to transcribe the Uzhorod (Ungvar)lists from 1937.
I have definitely come across the surname Szaiszlo in these films.
The site is best viewed using Google Chrome. I do not ask for payment, just a little of your time to help transcribe records on the projects page. Currently up to part 5 of the Uzhorod voter lists,.