Solax,
If you check out that link I posted they have a quite a bit of info posted. The blends that they have developed consist of a variety of clovers that are designed to provider continued protine through the entire period of antler development.

If you are trying to get this done as cheaply as possiable a 4 lb. bag should be pleanty. I worked the figures you posted 200yd.(600ft.) x 60ft = 36.000 sq ft. An acre has 43,000 sq ft. so for less than 40$ you can get the deer very good feed, that if left undisturbed will return for upto 5 years. If it only lasted just 2 year that still pretty cheep.IMO