I've always created swap of 1.5x - 4x RAM size on every Linux computer I've had to manage and never had any issues with it. That's my rule that I learned many years ago, follow to this day and will follow.

Worst thing: I left 5% of my SSD unused which will actually be used for garbage collection and other staff. That's OK.

What I don't understand is why modern Linux is so shy of touching swap. With old kernels, Linux happily pushed unused pages to a swap, so even if you don't eat memory, your swap will be filled with tens or hundreds MB of memory and that's a great thing. Modern kernel just keeps swap usage at 0, until memory is exhausted.