I am not RB, but the dry jelk is an old friend of mine as well. I’ll tell you how I do it.
I use my thumb and index finger only to move an ok grip from the base up to the point where I can’t really move it any more, usually about half way up the shaft. I do this while erect, so it’s mildly dangerous if you aren’t intimately familiar with what your equipment can handle and cannot. Also, doing this erect, I believe it more useful for girth and glans work than for length. I don’t know about RB, but I can’t get as much pressure with all three: thumb, index and ring fingers doing the “compression stroke”.
After about 10 minutes, the glans will be sore, and at this point I choose to lay off a while and do more later. If I go for too long at once, I have noticed that eventually some blood tends to appear at the exit of the urethra, which always freaks me out.
Something else I do: I wrap the left hand around the area forward of the OK grip and apply gentle pressure to it - increasing pressure very slightly as the internal pressures of the penis increase with each stroke. My hand encompasses about 80% of the girth this way. The reason that I do this is that, after a while, you will begin to accumulate fluid in the space between the skin and the internal structures of your penis. This fluid will place external pressure on the internal structures of the penis, thus reducing the internal pressure that is responsible for growth. Using my left hand in this way noticably increase the internal pressure that I feel from the dry jelk/uli stroke.
I hope you can understand that. It seems very difficult to explain.