I'm afraid I don't have much additional information of John Studdiford.
I am in the 7th generation since Captain John Studdiford, related through John's son Peter Studdiford. I understand that the captain died of yellow fever in the West Indies soon after his son Peter was born in New York. John married Catherine Brugher on March 11, 1761 at the First and Second Presbyterian Church in New York, NY. John may have originally have been from Penryn, Cornwall, England but I haven't found a definite confirmation of that.
An elderly Studdiford relative, Ellen Studdiford, died in Montclair NJ on May 5, 2004. She was 99 at the time. My sister lives in Montclair and had been trying to contact the family but without much success. It was said that there was an old trunk containing some old artifacts that belonged to Captain Studdiford. There hasn't been a follow-up since then.
I'll be interested to see your tree.