No worries! (As you can see, I'm replying with a bit of a delay myself!) I really appreciate your feedback on this; I'm super new to running a community, so any kind of input about what has worked/not worked in the past is super helpful.

Providing the prompts in advance seems to be the best way to go. I'm also looking ahead to my holiday schedule this year to see if there are any weeks where I just won't be able to keep the posting schedule, because I could deliberately plan two-week prompts (and let bannermakers know about that) for times where it looks like I might have issues.

Thanks again for the advice!