Yeast Starter Size for Maibock

I'm looking to make my first lager in the next week or so. I bought a Wyeast Boheiman Lager Smack Pack for the Northern Brewer Maibock kit (All-grain OG at 1.068). Should I let the smack pack inflate and then step up the smack pack in a starter once or twice?

For ale's I just normally make a 1L starter and let it go, but I've read a bigger starter is needed for Lagers. Looking for help. Mr. Malty says 3 smack packs, but what if I step up the starter from the single smack pack.

Do you have a stir plate?

no stir plate, I just use a 2L bottle and shake when I walk past it

What size batch are you making?

standard 5 gallon.

Used your Yeast Calculator.
If I figure this right, I should make a 3 step starter to get up over 494 ish billion cells.
If I get this right the steps would be:
1. Inflate smack pack and make a 1 liter starter.
2. Step up starter to 1.5L. - How long do I wait for this and should I decant and add 1.5L of wort or just add an additional 0.5L?
3. Step up again to 2L following the same step.

Hey, sorry for the non-response, for some reason I didn't get any notification that you had replied. At this point it's probably too late, but, the way I do it, is to ferment each step for 24 hrs. and decant in between steps. The way YeastCalc is set up is that the volume you enter for each step up is the amount of new wort you are adding to the previous step, regardless of if you decant or not.