This sounds like a pretty complicated mess, each and every time you port. I have found that there is absolutly nothing like experience
when trading. For example, I know that when I port with 250 holds of equipment and the port offers me 33,500 I can get 35,000 almost without fail. The 5 experience hits are nice bonuses every once and a while. However, I am able to get 2 points on a very regular basis, just by knowing how far I can push the dude at the port. It is rare indeed for me to not complete a trade, and rare also for me to not gain some experience at each port. Just a matter of knowing how far I can go with each offer made. EXPERIENCE is the best tool. I have a regular route that I take every day, I don't do pair port junk, because I want to be able to make money the next day too, and trading down the port messes that up. I can easily make 1 mill by following my route once.
I am currently in a 20,000 sector game that is fairly new and I have a 4 sector tunnel plus 3 other sectors that are full of planets. I have a mountain that is going for level 6 and 14 other planets that are level 3 or 4, besides some new planets that I started today. I have a formula for sector developement 2 earth, 2 volcanic, and 1 mountain. earth produce equipment, vol produce fuel and mountain produce organics. Takes a bit of moving stuff around, but this uses each planet to its best potential, and each sector is self-sufficient.
Once I get the planets maxed and the proper port in each sector (sbb), I will start raking in the bucks on planetary trades and then go hunting for firengal. And yes I have a fully stocked ISS and 3 other ships. My method works, playing evil or using helpers is for losers.