If the pond will be used as a swimming pond I wouldn't stock the Specklebelly Sunfish. I'd be concerned about the BG genes causing it to nip at swimmers.
If I was starting with a new pond, I'd put the plastic fish habitat in vs. the organic. The plastic will last a lot longer, add less nutrients to the pond, will be less work in the long run, and I feel will be better for the fish population. You can put the small, medium and large opening cover where it will do the most good and you won't have to be replacing it every few years as it decomposes.
| 
