Sorry, I had forgot that this was an already established pond... You may need to find a hatchery that sells advanced sized WE fingerlings. This hatchery
http://www.minnesotamuskiefarm.com/price_list.html sells 7"-9" WE for $2.00 each. At that size, they should be able to avoid predation. I would stock 150 and see how well they handle predation...
Weights cannot be determined by length alone, however a normal 15" WE would probably be a hair under 2 lbs. At 20", around 4 lbs.
If you decide to stock CC. Find the largest fingerling size you can find and afford. 12" CC shouldn't be too hard to find and would be immune to predation by all but the largest of your LMB.
