Here is a model comparison of a 5/8 wavelength antenna at the requested heights over real/moderate earth. The antenna diameters are 6 millimeters, which is just under a half an inch.
The v on the model names is for vertical, the number next to it is the height in feet.
As you can see, the gain goes up as you elevate the antenna, although the 0.84 dB difference from one height to the other won't really be noticeable.
Another thing to note here is the angle of radiation. The angle of radiation of the antenna at 65 feet is about half that of the antenna at 36 feet.
Now for some horizontal antenna dipole models...
The h in the model names is for horizontal, and the numbers next to that are, again, the elevation of the antenna in feet.
One thing to note here is the antenna's gain doesn't change much. Going from 36 to 45 feet of elevation, the gain actually drops, then beyond that goes up. Another point of note is the overall difference of 0.38 dB, which is less than half of the change from the vertical antenna models mounted at the same heights. This difference is insignificant.
The angle of radiation, however, goes through the same type of change with height as the vertical antenna above. Doubling the antenna's height again cuts this angle pretty much in half.
The DB