What an esoteric community - It would take me a while to work out what a thirty five point four is. Being a bit simple, and liking things easy, I'll vote for the "point" too. But I think most people wouldn't have a problem either way. F/14 would be "F fourteen" anyway, not "F one four".
Just learnt that US Air Force photographic reconnaissance aircraft from 1930 to1948 were designated the F1 to the F15. Very appropriate.