What size stir bar?

[Kubed]

Question for those of you using a stir plate with magnetic bar: what size stir bar are you using in what size flask? I have several laying around, but nothing I would want to try out on beer (read: used lab equipment). The starter wort seems pretty watery, but is an 1.5 inch stir bar going to be enough to move/vortex wort in a 1L flask?

 

[biggenius29]

http://www.northernbrewer.com/yeast-handling.html

I have a 2000ml flask and use the 50mm bar. For the 1000ml flask they say use the 25mm bar.