I like how you try to utilize so many ideas of different members to make things work for you and your goals!
Here is my first impression of mixing trout and CC. My dad's friend has a trout pond which stays naturally cold because of a fairly decent sized spring flowing into it and the higher elevation his property is located(around 3000'). Before he dug other ponds on his property, he mixed some CC in with the trout. No blocking net, they just were held together. The biggest thing I saw was the CC just didn't grow fast. They survived, but growth rates were slow even with supplemental feeding. I think that may be one of your biggest challenges in a dual pond like this.
Even if the CC and trout are separated by a blocking net, which I am not sure is even needed... The water temperature on the CC side is pretty much going to be close to the temperature on the trout side. The net isn't going to effect the water flow between the two sides. Even if you dig the trout side a bit deeper. The use of an aerator would have to probably be utilized the way AP does and that is have it set to only run when air temps are below say 68 degrees. How many nights in the summer does the air temp drop below 68 in your area? The deeper aspect would be helpful in giving you more water volume allowing it to maintain a cooler temp through a heat spell. However, you're gonna have to run that well water a lot in the summer I am guessing... Cecil is the man to ask when it comes to that. Perhaps, you can send him a PM and ask him to post his thoughts and ideas on this as well...
As far as feed, use trout feed the catfish will do just fine on it, but not vice versa. I don't think GSH are too fast for CC to feed on. Once CC reach the 2 pound range, they are efficient piscavorous predators. If your purpose in this pond is to grow catfish to eating size and then harvest them, the need to stock GSH is not there. FHM would do fine. FHM will usually hold up in numbers when only CC and trout are present. Now if you plan to grow CC larger than a couple pounds, then you can consider adding GSH. Remember though, you're planning on feeding pellets so the CC and trout will be obtaining most of their food via pellets in all likelihood. GSH may get too big for the trout and CC and you could have issues with that, so that is why I would hesitate adding them even if you plan on growing the CC larger than 2 pounds. Rely on FHM, bluntnose minnows and pellets to feed your CC and trout.
To wrap it up... I don't think you even need a block net... There is no reason you can't mix trout and CC IMO. Unless your growing 8 pound plus CC which would then prey on your trout, they will live together fine. I think you will see greatly reduced growth rates in your CC if they are kept in water temps suitable for trout but they will grow. Feed them trout feed and both the trout and CC will grow fine. See if you can get Cecil to weigh in on how much well water pumping you're gonna need to keep the pond cool enough for trout. I think that is going to be the biggest challenge... Keeping the pond cold enough and oxygenated enough through the warm summer months. A combination of well water, aeration used in the correct way may allow trout to survive the summer, but I think it will be a challenge.
Best of luck and keep us updated on what you decide to do...
