Starter Stepping: How big can a 2L go?

[cosmatics]

Hey figured I would ask HBT and see feedback from the collective. I plan on doing needing about 500 billion cells for about a 6-7% lager. So far I have stepped up a smack pack of Wyeast 2124 2 times on a stir plate in a 2 liter flask so about:

100bil ==> 200bil ==> 350bil (based on Chris White's Yeast book)

Can I step this up one more time in my 2L flask or should I split the yeast in half and step that one up?

 

[Begin2Brew]

Your growth rate will be higher if you split it and pitch half into a 2l starter.

 

[EODstads]

your growth rate will be higher if you split it and pitch half into a 2l starter.

+1

 

[cosmatics]

Cool, since I only have one stir plate and 2L flask at the moment, I guess I will just split it and give it one more ramp, which should get me about 175bil + 350bil so definitely in the +500bil range.

In the future if I'm going to do bigger batches do you think it makes sense to get a 4L flask?