in my experience you don't want to focus on the 'fireworks' when trying to WILD. For me, in order to WILD, I just lose awarness of my visuals, just like I was falling asleep, then at the point I notice a discernable object I focus on the object and a dreamscape slowly forms. I learned to WILD by using WBTB and it just naturally started happening. I stare at things like fireworks while meditating, if im persistent enough it usually leads to more complex visuals, but unfourtenately I've never once entered a trance or a lucid dream while meditating.