Great input everyone.
Robin: I'll surely keep the algaecide in mind and watch for algae.
Larry: I love hearing about all your experiments. I hope your mild winter continues and you have a bumper crop of seedlings. I can't wait to see (in bloom) pics of all the seedling beds you have.
Greg: I always start seeds in the paper towels. I think this year I will do up one tray by sowing directly from the frig and see how it goes. It would save a lot of time messing with the baggies. But honestly, I rather enjoy watching for the little root to show its face. Of course I don't do this on a large scale. If I did, I'd probably direct sow for sure.
Elena: When you say "they tend to outgrow it really quickly so you'll need to transplant sooner rather than later", do you mean they grow faster with the mat?
Perhaps because they are getting 'more consistent' moisture?
Or do the roots eventually want to plant themselves into the mat? I wondered about that and figured I'd just remove the mats if that happens.