Here is a relative weight chart for LMB. It starts at 12". Catch some, weigh and measure them. They might weigh less than the chart if they just came off of spawning.

http://www.fish.state.pa.us/images/pages/fishin1/weightlength3.pdf

www.hoosierpondpros.com

[Linked Image from lh6.ggpht.com]
http://www.pondboss.com/subscribe.asp?c=4
3/4 to 1 1/4 ac pond LMB, SMB, PS, BG, RES, CC, YP, Bardello BG, (RBT & Blue Tilapia - seasonal).