I just figured out that c/guitars sorts to the bottom of the Subscribed to communities box on https://lemmy.world because the Display name isn't capitalized like most communities. Where did you get the icon you used for the community. It really fits with the overall aesthetic used in a lot other communites on this instance.
My guess is the discord servers will grow immensely. Lemmy seems like it could work too although I dislike how i have to sign up for several different servers. IMO, that's a huge drawback and I'd much prefer being able to find a discord dedicated to one hobby or topic and have them neatly organized in my apps across different platforms rather than having to dig around across different Lemmy servers for my interests. Is there a way to aggregate all the lemmy servers into one feed?
I'd advise you post in more general communities for now. Lemmy is very new. As far as I've found this is the largest guitar community and the vast majority of posts get no comments. Best to build up this community where there are at least some people already than posting into an empty room.