To answer your question, I have a feeling there was a duplicate before, but I think probably the approach is to see where you would have placed the track/s and tally the scores and divide by two.
You seem to have a pretty good handle on things already so feel free to ignore the stuff below, its just unsolicited advise based on what I have seen as a pretty avid follower of all things Walrus on this forum :-)
Entry pool size
Obv the more contestants, the more songs to listen to, then factor how many times you listen to each track, then doing the review piece. Generally people limit it to around 12 somewhere. I would really suggest not going much above that.
Categories
I found these harder than expected. I think 5 is a pretty good number to start with. There are kinda two ways to look at them.
One is to list something specific/niche. For example, a song by a band from Italy. Or a song that involves a flute. But generally a category like this requires a lot of contestants to go googling for anything that fits because they know nothing offhand. So they really don’t have much of a personal connection or appreciation of that song, which makes it less fun to submit and get your take on.
The other option is to be more broad, but still be mindful of something you want to hear. “Something that would get you pumped up at the gym”. “Something from the 90’s”. “Something where the vocals are unusual”. “Something that evokes this emotion”. Stuff like that. In my opinion these broader categories make for a better game for everyone.
Your musical tastes
As LouisCyphre said above, I think you will probably enjoy hosting more if you at least loosely define your musical preferences. It gives people something to aim for. Or at least call out the stuff you really don’t like.
General disclaimers
Hope none of the above seems overbearing or makes the idea of hosting seem less fun. Despite my enthusiasm I am not an authority on the game, so you do you! I also always like to point out that ChrisV was the first one to bring The Walrus to unstuck. You can see his signup thread at ChrisV's Walrus and the reveal thread at ChrisV's Walrus - Reveal Thread.
Thanks I think this is all good. I have categories in mind that I think are reasonably broad and I think I might give an example for each category that would then be off limits.
There have been 14? or so Walruses. So that’s about 42 songs that have podiumed. How about a bracket tournament to find the best all-time Walrus track? Or go the other way and have a best of the nodium tourney.
Could have committees make a 64 song bracket for each and then have a vote? I haven’t read any of the other music tournament threads so I don’t know how they’ve been handled. Sounds fun and I might be willing to help depending on my schedule.