After reading someones on here statement saying they get a more powerful trip on dmt through a short bong then a long bong, i experimented. (possibly placebo) but my experience with just 4 more inches of height by my new bong was weaker then the experience was with a shorter bong. Can anyone confirm this or how it is so? I'm thinking about taking the new bong and cutting it in half.

It depends on vapor densitiy and volume. A good vaping device like the VG allows for really dense smoke, so the chamber of the GVG is big enough. A bong, perhaps with a brillo filled chillum and cone might not produce a vapor as dense, so a bigger volume pipe might be beneficial if you were to take only 1 hit.

Because vapor is propably most dense in the beginning of vaporisation, a bigger bong would be detrimial to your efforts, because vapor would get more dilated by regular air. This would lead to a smaller dmt intake per inhalation and, if therefore to a potentially weaker experience in terms of intensity.