TR one additional point to consider is that TShad have/use a different niche in the pond than do BG. As a result if you can establish TShad you will be using a greater part of your pond's ability than you would without them. That is a big plus to using TShad. Also from a nutritional aspect they are an excellent LMB food as they are high in lipids (fish oil).

Like Greg said , insist that they be pre-spawn adult TShad and stock them a little while before they spawn. That gives you a much better chance of being successful. Good Luck and report back what you decide and the results.