choosing minhagim

Question

kvod harav. My father did not keep kosher until i was an adult, though the house was kosher becauseof my mother,and i was raised in yeshiva(how this worked out is a whole other story) from meat to milk, would someone llike me be free to choose whichever minhag i wanted 1,3, or six hours, for that matter if i knew the custom of the land my his parents came from, would that make any difference. he was born in vienna, and his parents home wasnt kosher 2/ speaking of choosing minhagim, when a gentile converts to judaism, are they free to pick sepharidic or ashkkenazic minhagim,: doesit depend on the rav who converts them? thank you