Sounds good growing! Yeah, the thumb just being there will help, you’re probably using it a little bit without knowing it - just pay attention to the feeling in the top shaft of your dick, especially near the base.
As far as girth gains, it did swell a little during ballooning, but I could never get the girth gains that the guy in the pictures got - they were… dramatic.
You don’t have to get close to ejaculating, but when you do, the effects are most noticeable, so take your time with this - give yourself an hour, and see what happens.
But 1/4 is a great start, keep it up and keep us informed.
Just to make sure I have everything correct, why is the feeling in the top of the shaft near the base so important? Also, why do you want to avoid the under side of the glands? What’s so significant about that? Though I can’t be sure, it seemed that while I was ballooning earlier I was comming into contact with the underside of the glands.