For the record, I've been mostly out of pocket lately, during which time received a private message asking why I had added the PGM tag to the Briggs profile.
Answer: I went to the profile to see what this G2G was about, ended up editing the profile to remove non-meaningful clutter that was getting in the way of reading it, and added the PGM template because (1) this G2G was tagged with the PGM template and (2) I saw a source that mentioned possible immigration in the 1630s. I didn't do more because I had no info to supply. It's now clear to me that the John Briggs on a 1630s passenger list (also discussed in GMB) was a different man. Does he have a profile yet, to help reduce the potential for confusion?