Technology comes full circle
I moderate online meetings from time to time, and I've tried different approaches. For some time now, I've been using a circular slide rule. It's fast, it's easy, it's small (inconspicuous, if you're working in front of others), and the circular slide rule ensures you never have to re-orient the rule. If you'd like to try this approach but don't have a slide rule sitting around, check out Concise. They make a variety of circular slide rules. I'm using a smaller, pocket-sized model they no longer make, but I'd be interested in their 300 today. For this work, though, the 27N or 28N would do quite nicely.
If you're not ready to buy one, consider a home-made version.