The glans will expand proportionately with the shaft of the penis under the normal stresses involved with jelqing and other pressure inducing exercises. The glans is a robust character and has its own protection mechanisms that shield it from excessive stress and manipulation. Its the end of the “pipe” and takes the most stress in copulation and general sexual activities, if it were not designed in this way it would be like a soda bottle blowing its cap at abnormal pressures.
The exciting thing about penis size is that even a small incremental growth in circumference has a very noticeable visual effect. I have had success growing the glans by applying stress loads during hanging that balloon the head beyond any normal range experienced in your common jelq techniques. You have to hang with about a 50 percent erection and maintain that erectile quality throughout the 15 - 20 minute set, it will help to stimulate the frenulum during the hang to keep optimum erectile strength to the glans and therefore a “good pump” to the glans. You have to develop this technique and find the location on the penis shaft that gives you the best tumescence to the glans; sometimes the immediate base translates to maximal engorgement of the glans, other times it is a bit forward of this position. Ultimately, the head size will develop as blood pathways expand, as these pipes grow in girth and hold greater volumes of blood, the glans size will increase. It is a slow process and requires a disciplined approach and consistency.
In many circumstances the head requires a slow build up of blood to obtain its optimal size. Another words, you have to manually pump blood to the head by jelqing strokes to manipulate the head to its greatest visual appeal. Its a little bit like stuffing sausage skins or packing a leaf bag, you can stuff more blood in the vessel and thereby achieve maximal expansion. In most cases you can get more blood in your penis by repacking it (if you will), of course, you have to have a well conditioned penis through good PE techniques to be familiar with this phenomenon.