Eric from your pics you have your returns just dumping in the sock.
You should build an other Durso type stand pipe for the sump. it will cut down on some of your bubbles and lots of noise. just make sure it empties just below the waterline and don't forget to drill the top.
IMHO, your bubble problem is from the dual overflows and the small pump mixing to much air with water, If you had the volume of water to demand two Dursos you would have had to gut the teeth on the overflow or have water flowing over the top of the tank.
In other words you are not supplying enough water to fill 2 pipes so the remainder of the space has to be filled with air, it mixes together during the fall and so you have bubbles.
In my 65 I am pushing close to 1500gph through a 1" drain 1 1/4" Durso with only having to enlarge the space between the teeth.
I have had twin Dursos before and it takes a lot of work and understanding of how to adjust them to get them to work well together without flushing. (I'm doing something different with the 150 to avoid the difficulties, based on personal conversation with Rich Durso)
I'm not clear on your vision of what you want with this tank but think your going way beyond what you need and getting frustrated because it isn't working how you envisioned it.
Remember KISS (Keep It Simple Stupid)