Hi mate, this topic is of great interest to me as I've been researching this very thing. The best knowledge by far was obtained from Dr. Bruce Bugbee. UVB is important if you want to increase thc and other cannabinoids. However, the light should only be used in the last few weeks of flower, for no more than 2hrs and midway through light cycle to simulate midday sun.
There are many reasons for this but the most important ones are:
UVB is dangerous to plants it mutated them. Same way it mutates human skin. Therefore too much will damage your plant, which could be unseen.
Using UVB throughout the grow, especially in veg. Even in small amounts the plant will develope a resistance to UV light. So by the time you get to flowering, the light doesn't have the desired affect.
You need to shock the plant to defend itself. Hence creating more resin. This can only be done late flower.
I hope this helps. Happy growing and good luck โ๏ธ