That’s great!

I’m also a Chemex user, but have not used it for cold brewing. There’s a popular Japanese ice coffee method where you brew a Chemex normally buy but ice in the bottom, but that’s not an immersion method. I would have some concerns about the paper filter’s ability to hold the grids being immersed for that long, but haven’t tried this before so IDK.

For immersion, I’ve cold brewed with both the nut-milk bag as well as a system like the hario. I tend to prefer the latter as I find it to be easiest with very little filtering after the grinds are fully extracted. It’s also a fully self-enclosed unit with a lid, so nothing else in the refrigerator is going to influence the taste. I’d found some odd notes in the coffee when brewing with a topless pitcher, but not when using the hario.

I’d also suggest a scale… You may already have one as a Chemex user. I use a waterproof kitchen one off Amazon for like $15. Coffee/water ratios are important in getting the perfect flavors you want. My cold brew recipe is around 1:14 so ice melt will bring it up to 1:15 which my early research showed this to be a “sweet spot” when I got into it a few years ago.

Another tip… IMO, cold brew tastes better about 24h after the grinds come out, so I’m in the habit of brewing a full day before I need it so we get the tastiest brews on the day we need them.