have you put proofhide on your Brooks? I used to feel like I was going to slip off mine too, early on. The proofhide will make the leather surface "sticky"
so it might help. Suddenly, you're going to feel quite good up there.
If you've ever ridden a horse, on an english saddle, it's the same sort of thing.
You feel like you're just perched up there and could go flying off at any time.
but then you "get it" and you don't feel that way any more.
Glad that you are making little adjustments and noticing the difference.
I rode 100 miles this weekend on two different brooks, and I have no saddle pain at all.