Yes, it is a low to medium force technique (it can go very high force, but it is counterproductive).
If you keep your vacuum at or below 5 in hg, you can get good steady progress, especially if you add jelquing ala pumping 101.
As with any method, when you hit a plateau, you should try a deconditioning break, rather than pushing the vacuum up much past 5 in hg. Most of the pumping vets who have gotten excellent results report that the lower vacuum is far superior in the long run for gains. Its far better to add time, than keep pushing vacuum forces higher and higher.
I think the important thing to remember is high vacuum will give you a huge dick IN the tube, but you lose all of that and sometimes more after you get OUT of the tube.
Lower vacuum levels aren’t that impressive IN the tube, but will result in good steady, SAFE gains out of the tube.
Remember, this is living tissue, and if you stress it too much, it will result in inflammation, contraction and stiffening of the tissues…all bad news for PE.
If you go from pumping to clamping, you can see additional gains because of the much higher forces that are being used. However, when you hit a plateau from clamping…and you WILL…the decon break needed will be far longer.
Plus, I am of the mind that clamping will all but halt length gains until a long decon break is taken. Of course this is just my opinion.