Yeast starter - 2 stage

I have been making 1.5-2L starters for some time now, but recently I have been trying to follow the recommended pitching rates from Mr. Malty and others which involve pitching more yeast than I ever have, at least for lagers. My first question is, is it better to make a single stage large (~1 gallon) starter or make a 2L starter, then do another large 4L starter?
My next question is on the process of doing the second stage of the starter. Hopefully I get some feedback on this process.

1. Make 2L starter (2L water, ~2 cups DME)
2. After 48 hours or so??? or after all activity stops?? put starter in fridge
3. at least 12 hours later make 4L starter
4. decant all of the liquid from initial starter
5. pitch all yeast?? from first starter into second starter?

or, if you're cheap like me, you could make the 2L. when it comes to a krausen, dump in another 2L. i don't know the exact cell count from either of the two ways, but the beer has always turned out good. go for it!

your process looks fine, but i bet you won't need to wait 48 hrs. but generally after activity stops, i let mine ferment out all the way if i'm stepping up. you can grow more yeast if you decant all the liquid and then put half of the yeast into a sterile container (an old white labs vial or something) and then put your next step on the remaining half of the yeast. but you can also just dump the new wort into all of the yeast and you will get some growth, just not as much as if you do it the other way.