Welcome to the forum. Thanks for researching your question ahead of time.
As you have found, your questions and related ones have been discussed at some length on several occasions. I can't know what threads you actually have seen, but here are two, one of which contains links to still others.
http://www.medhelp.org/posts/STDs/HPV-and-oral-sex/show/1515473
http://www.medhelp.org/posts/STDs/Oral-HPV-Cancer-Risk/show/1512873
I don't agree with the implication that the reasons I have given for concluding the risk of oral cancer is low are not "objective" or "concrete". The simplest argument, however, is perhaps the most robust (as well as objective and concrete): with only somehwere around 10,000 cases per year of HPV-16 related pharyngeal cancer per year in the US, millions upon millions of oral sex events per year, and at any point in time a few million genital HPV-16 infections, it is obvious that the proportion of oral sex events that lead to such cancers is exceedingly small.
Data are scant or nonexistant on the actual frequency of oral HPV-16, the efficiency with which it is acquired by oral sex, other potential (nonsexual) transmission modes, and clearance rates. Ongoing and future research may address these issues someday. To my knowledge there are no data on whether childhood tonsillectomy further reduces the low risk of pharyngeal cancer, but my guess is it makes little or no difference.
My advice is that you seek a more realistic perspective on this issue. I think I recall a statistic that cancer causes about one third of all deaths in the US. On that basis, there is a good bet cancer is what will take you from this world someday, but if so it isn't likely to be pharyngeal. Colon/rectal, prostate, and lung cancers account for the lion's share of cancer deaths in males in the US; by comparison, pharyngeal cancer is very rare. Based on currently available knowledge, it isn't something to be worried about, regardless of oral sex exposures history. And in any case, I would view "oral sex on 6+ women" as a rather low number; I would give the same advice to someone with 100+ such events.
I hope this helps. Best wishes-- HHH, MD