Is a 1020 tray the flat trays with no holes? If it is, I tried putting my plug trays in them but they seem too tall and my sides bowed out. Anyway, the capillary system is good. I used to use APS from Gardner's Supply. Love them, but just didn't use this year because of the volume.
I thought about using the inserts but again, my volume demanded the plug trays. I did get some 128 plug trays after I finished so next year I can do larger seeds and/or not have to transplant so soon. But like your watering, I just cannot resist it!
Potting mix, potting soil, it's all pretty much the same here. WOOD, not soil! I don't have a favorite brand, we try and get the broken bags since I make my own mix.
