I think there are too many branches in your willow bundles of willows. Make them about 1/2 as big but make lots of them. I would not weight the bundles especially since they will decompose relatively quickly. Just place the bundles in the pond with the trunks on shore so branches are in 12"-24" of water. Fry to 1.5" long favor the shallowest water close to shore for refuge-cover and feeding what periphyton associated organisms live on and among the twigs. When the small twigs decompose just easily pull the trunk bundles out and replace them with new bundles. Make some bundles my method and some your method; compare results and do what works best in the future.
Also look through the Structure ideas in the Archives Common Pond Q&A for additional ideas for small fish cover.
http://forums.pondboss.com/ubbthreads.php?ubb=showflat&Number=92463#Post92463Dandy bluegill you have grown there in Colorado!. Be watchful as the fishery develops that you keep big BG coming into the population as those old big ones die at ages of 5-8yrs old. Expect that big male in the picture to live only 1-2 more years.
