First, subsribe to the Stockman's Grass Farmer,
http://www.stockmangrassfarmer.net/index.html
They also have lots of good books on the subject, I've bought most of them, read half of them.
Are you aware of the health benefits of grassfed beef? Omega-6 to Omega-3 ratio and CLA are the big ones.
If you aren't using lush grass you won't get the health benefits. I wouldn't use an old grown up meadow for a finishing pasture, nor for the stocker phase. That sounds like cow pasture.
One strategy is to take your best pasture paddocks, send the finishers in first to select the best stuff then send the next group in behind them to graze the rest down to 3-4" You don't want to let the grass get much more then 8-10" for a grassfed program.
I will reiiterate the point that grassfed takes Management Intensive Grazing (MiG), they don't call it that for nothing. It's also recomended learning MiG with Cows before stockers or even finishers.
What is your market? How far from a city are you?
I've been switching to grassfed the past year. I have probably at least 200,000 people living in a 30 minute radius. Whole Foods Market is building a new store that will be finished next month. They want to buy grassfed beef direct from the producer. There is a local farmers market starting this spring that is asking me to join. That is located in a town Called Windham, Maine that is on the East side of Sebago Lake. There is tons of tourists in the summer going to their cabins/cottages and to the lake. The location of the farmers market has been researched to have daily traffic counts of 25,000.
I sold my sides of beef direct to customer this year for $2.25/lb hanging, that's just for the animal, no processing yet. They pay that to the butcher. I don't think I'm charging enough. Once I get better and more consistant I plan to charge at least $3/lb. One farmer I talked to this week is charing $3.50/lb hanging with processing included. If you don't have a good market then Tall Grass Beeef Company will pay $1.75/#, I believe that's hanging, if you meet certain requirments. One of which is an ultrasound test of the ribeye and backfat at a certain age.