hi! right now im only doing invite only zines because i have my hands tied with other work and small business stuff :') i loved doing zines in the past but now i just don't have the time and i only have been doing 1 zine a year in recent years. so maybe it's best to move on from my zine arc idk!
i think both closed invite and open application zines are great, but of course you have to make sure the moderators know what they're doing + their carrd/website has all relevant info! for the closed invite zines, im usually working with someone ive worked with before. zines headed by new/unfamiliar mods are worth a shot too. everyone starts somewhere. but again you have to screen the project and make sure it suits your work schedule and if the mods/project are reputable.
(and again this is to clarify im speaking about large scale fandom zines, not about comic/self printing zines, zines with friends etc!)