Interesting questions, those. And like many questions, they serve more to illustrate the nature of the questioner, than to direct the discussion.
Is "this site" reliable? I could wonder whether you meant this forum here, or the reference to phimosis on Doug's Method page
, or the illustration from Doug's site
? Well, there's the point - the site is there (and has according to the file dates, been there for a couple of years), it is neither reliable or unreliable - it's just a description of a technique which seems to us to be the most effective approach.
The most effective method as it is said, is the one that works. If you can do the stretch as illustrated
there, than that would seem to be the way to go. If you can't get two little fingers to fit for a start, then you may have to improvise with one finger, working up to the largest (thumb).
I can't see how the size of your penis would be of any relevance.
All the matters you mention are well covered on other threads here. The sensitivity of your penis head will be pretty much the same as that of your girlfriend's clitoris - that's how it should
be under normal (i.e., not circumcised) circumstances. You probably figured when you got your foreskin stuck, that you could have done what the doctor did, earlier and easier - if you had realised that was all that was necessary.