Not sure.
It depends on the individual.
Some gain only length, some only girth, some both, some none, some develop the baseball effect (= more girth mid section than base; due to incorrect form), some get more girth at the base…
Some gain fast, some slowly… Some need to adjust an aspect to the routine - be it technique, intensity, volume or on-off schedule to see any gains..
There are simply too many variables to give a response to you!
Recently I have read somewhere that increasing glans size is very difficult because the required intensity to exercise the glans even a little bit would make your shaft explode
and there is simply no exercise that singles out the glans only where you could simply do that.
I am not sure if this is true though! Because when I jelq, my glans balloons up and seems like about to explode!
When you are jelqing/milking, you are repeatedly forcing blood to move up to your glans and without giving it any chance to escape, you pretty much trap blood there
and keep pumping/milking new blood to the glans, forcing it to expand.
DO NOT misunderstand though, as a newbie you might think this is all happening forcefully - NO.
I am talking about 20-30% erection quality (aka boner status) with light, slow jelqing movement with 0 pain or anything close to pain!
So, do not get the wrong idea. Do not go and rip your dick off! I suspect many fall victim to this - they simply misunderstand the written word, thinking they need to rip their dick off!
Good luck anyway!