Checking germination in older onion seeds

Last spring a friend gave us some onion seeds he had saved from the summer before. I used about half of them last year. I also saved seeds from some onion sets that we had bought and planted last year. So this year I have 2 types of onion seeds to grow, but onion seeds don't last very well, so before I spend my time on them and give them space, I decided to check their germination rates.

This evening after I put Little M down, I got both types of seeds out, and gathered together a tupperware container, some paper towels, and a spray bottle of water. First I put a folded paper towel in the container, then sprayed it to get it damp. I put a dozen or so of the older seeds in the paper towel 'envelope', and then folded the paper towel over top, and sprayed it again. Then I did the same with the seeds I saved from last year. I sat the lid lightly on top of the container to keep the moisture levels up in our dry climate, and set the container at the back of the counter. Now I wait about 5 days or so, and check the percentage of seeds that have germinated. I didn't need to check the newer seeds, but I figured it would give me a control so I knew whether the old ones should be germinated.

Hopefully they will both germinate fine, but if not, this way I will know whether I should seed them denser than normal, or toss the seeds entirely if they don't do well on this germination test. I still haven't decided whether I want to start my onions inside early or direct seed them later...