My TA was around 60 so that is why I added baking soda. Low TA and aeration is what caused erosion of my plaster so I am worried about that and was shooting for a mid-range level.
It is not just low TA and aeration that can dissolve plaster, but also low Calcium Hardness (CH) and low pH. It is the combination that you want to saturate the water with calcium carbonate. So you can readily have a lower TA level of 60 or 70 ppm if you don't lower the pH as much and you raise your CH level. A higher TA will have the pH tend to rise faster. I'd shoot for 70 ppm and raise your CH as needed. Let's say you plan to keep your pH in the 7.6 to 7.8 range and that you have your CYA level at 80 ppm (to minimize chlorine loss so you can turn down your SWG on-time) and have a minimum FC target of 4 ppm. Assuming 3000 ppm salt, you could raise your CH to 500 ppm to have a saturation index of -0.2 at pH 7.6 and 0.0 at pH 7.8 which should be fine (you could have your CH at 400 ppm and probably be OK since your pH tends to stay towards the higher side).

What are the Borates for, to lower my TA?
The 50 ppm Borates are for additional pH buffering that should slow down the rate of pH rise and also prevent scaling in the SWG cell.

My pH generally goes from 7.6 to 8.0 overnight.
This is probably a combination of your TA being too high and having the short pipe runs not fully dissolving chlorine gas. The use of 50 ppm Borates will also slow down this rise though won't change the amount of acid you need to add. Having your CYA level at 80 ppm will help because it will protect chlorine from sunlight more even with the FC higher to maintain a 5% FC/CYA ratio (i.e. 4 ppm FC with 80 ppm CYA). Losing less chlorine to sunlight means you should be able to lower your SWG on-time and that will reduce the rate of pH rise since there will be less aeration of the water from the hydrogen gas bubbles and less chlorine gas that escapes.

I do have short pipe runs. The returns are aimed so that it barely ripples the surface of the water. What is the correct way to aim the returns? Should I aim all 5 of them down?
I would point the returns that are closest to the pump downwards or diagonally downwards (depending on the type of flow you want). You'll probably need to keep some returns pointed so that you get some surface water motion to be able to move debris to the skimmer.