DLD, I'm going up in 1/8" increments. The exact bar length doesn't matter imho, because you can adjust the screws a full inch easily.
To the original poster: I don't measure from the tip, because it doesn't really make sense to me. Your head is a lot smaller when it's in the
extender than when you're erect. I measure from the base of the head, right where the rubber strap sits. Currently, I keep that at 6", which is right where the base of my head is when I'm at MAX erection. (the head adds 1.625" erect, but only 1.25" in the stretcher)
I started at 5.75", and I've only gone up 1/4" since I started using it, but I'm definitely getting a good stretch. My flaccid hang is up 1/4" in 3 months and I'm only averaging 2 hours a day. (I'm now up to 5.5" flaccid hang, and I started Penis Enlargement at 4.75". Gained the first 1/4" from manual stretching)
I have the bars set so that when I put it on, it ranges from 5.75-5.875", and then I use the screws to fine tune it to 6". I generally never let the screws go all the way down or it pinches my scrotum.
In my opinion, you should use as few bars as you can, and rely on the screws. This makes it much easier to put on the stretcher. But, to each his own.
I definitely love the feeling you get when you add another 0.5cm bar.
Tom