I don't use the twisting screws to add tension. Every time i use it they elongate in different parts and they don't end up equal lengths. I just add of the rods.
I think you may be putting too many rods on before securing the strap. If it is too long and needs to be extremely tight to hold your unit in the
extender, you are trying too much. Just go steady. If you're 7 inches BPFSL don't make the
extender rods up to 8.5 inches long as you will not fit. You may strap in but your dick will pop out as soon as you let go, unless you do it very tight and cut all the circulation from the glans of your penis.
Also, the
extender works the Tunica, a very tough muscle which is not very elastic at all. If you over do it by trying too much, you can get what some people call 'the cord'. It is where the Tunica toughens up and can be felt like a wire under the skin. If you get this, you will not gain until it has subsided. It won't subside if you carry on P.E. You will need to take time off from P.E. if you have this injury, which can result in lost gains.
I'm not saying you will get an injury, as you may not be injury prone, but i'm just warning you that there is no rush. Penis Enlargement isn't a sprint.