Will this work for stepping up lager yeast starter?

[Rubes]

I am making a starter for Wyeast 2206 Bavarian Lager tomorrow. According to Mr. Malty I will need 323 billion yeast cells for a 5 gallon pilsner with an OG of what should be ~1.046. I watched the stepping up a yeast starter video on billybrew.com and while it seems pretty straightforward I want to make sure this method will work.
I'm going to boil 2 liters of water to 200 grams of DME and after its cooled I'll pitch the yeast into that. When it's done I'll decant the liquid, and I should now have 200 billion cells. Can I now just add another 2 liters of freshly boiled DME on top of the yeast that's in the container, and this should multiply itself to 300 billion? Is that close enough?

I'm planning on brewing on sunday so I want to give myself plenty of time with the starter in case it takes some time to finish fermenting. If it finishes quickly will it be okay just sitting in the fridge for a few days in the container, not having any more sugar to eat? I hope this will work, or I really misunderstood something.

Thanks

 

[samc]

Someone recently put this website together that does the calcs that Mr. Malty doesn't do for step ups ! YeastCalc Yeast Calculator , works very well.

 

[Rubes]

That's an awesome calculator, thanks!

 

[Rubes]

I made a 1.5 liter starter on tuesday, and after about 12 hours it really took off. I've been swirling it around every 10-20 minutes (except when I'm sleeping..) for the last 24 hours, and everytime I do it foams up like crazy and I can hear all the gas escaping. When will this thing be done?? I need about 300 billion yeast cells, so I want to step it up with another 1.5 liter starter after; I figured it would be done by this morning and I could put it in the fridge for the day to settle out the yeast before decanting. Should I just put in there anyway and fill it back up with fresh wort for the next step up, or wait until it's totally done done fermenting?