Starter help

Hello All
I plan on making a 1.120 barleywine and have read much about yeast starters and Im pretty sure I would need to make a 3L one to be safe and have enough healthy yeast to ferment all that sugar!!! My question is that I have read that you should add a half a cup or DME to every 2 cups of water, so to make a 3L would i just up that ratio until it equals 3L? Or should I make a starter with 1/2 cup DME and 2 cups water, let the yeast multiply, then when they seem to be done add another 1/2cup of DME and 2 cups water, and repeat this until it equals 3L?
Thanks guys

I wouldn't use 1/2cup measurements. You'll want to weigh the extract to be more precise. Personally, I use 3-4oz of light dry extract and dissolve it in 1L of water. If I have to step it up to 3-4L's, then I'll let the first one ferment out. After it's done fermenting then I'll cold crash it in the fridge for 48 hours. Then I'll decant all the liquid and leave the yeast cake behind. Then I'll add another liter of wort to this and let that one ferment out, etc., etc. Keep doing this until you've made enough wort to equal 3-4L. Check out Mr. Malty, because I think you'll need a bit more than 3L.

About 4 cups per L, about 1 cup DME per L, so about 3 cups DME and 12 cups water, yup.

If stepping up, you usually do it more geometrically...so yeah, you could make a 2 cups water starter with 1/2 cup DME, then add 10 cups more water and 2.5 cups more DME to bring it to 3L.

Weighing is better, but who is to say that 1.037 OG starter is any better/worse than 1.045 OG starter? Just eyeball it if you don't have a scale. If you DO have a scale, it's 11 grams DME to 100 mL water for 1.040 OG. For 3L this is 330 grams DME.

Thanks guys
I was planning on using champagne yeast to dry it out a little more then a usual BW. I used the Mr Malty calculator and it said that I could use 4.4 packs of dry yeast. I think Im just gonna pitch like 5 packs of dry champagne yeast. It would still be cheaper then buying 1 wyeast pack. But thanks for the help