Sterilizng Flasks

[brsucculents]

Ok, I've never done this before but I've read all the posts on germinating seeds at home with glove box. I was hoping to use wide-mouth pint canning jars for flasks HORIZONTALLY. Horizontally because it allows better light penetration, two fit nicely across a fluorescent light fixture, extra room in a flask. The problem is how to sterilize jars horizontally in a pressure cooker? I believe you can't stand them up because the media will solidify on the bottom but horizontally in a pressure cooker, you can't stack jars, water can get into the bottom jars...
Any suggestions? Surely others do this, right? I believe Troy Meyers uses flasks like this.