OOC:
The Polo has 81 tons of cargo space.
The Bleue Mer supplies will take 20 tons of that, leaving 61 to play with. The chances of that much suitible speculative cargo from anywhere to Bleue Mer are roughly nil, officially there's nothing there but a research station. You can fill up with a few luxuries and comforts for the staff and because it's probably very boring there they need any sort of entertainment (ie: Media & Booze, as well as hobby materials.) That will fill up a dt. The other 60dt will be ballast, and the chances of getting a cargo out are nil. Fortunatly, Pharmacorp's terms asume that the trip from Bleue Mer will be in ballast, so you could just fill up with fuel for free and jump out.
It looks like the most profitable route to Bleue Mer is via Shirgegge, that agriculturla equipment needs to get there urgently and the price offered has gone up since you first checked. The shipper looks a bit desperate. Some further digging reveals that there are several people willing to pay very good money to get there, get their feet in the door with the K'kree and do some negotiating. Very good money indeed, though some of them are the sort of people used to high passage they aren't being too chosey so long as they get there.
A query with the shipping agent for Pharmacorp turns up that they have a consignment of animals at a facility on Shirgegge, as part of a program to adapt them to Bleue Mer - this will fill up most of the 60dt that would otherwise be empty.
Shirgegge easily looks the most profitible, if you don't mind having your state rooms filled with yuppies on the way there, and your hold full of smelly animals and straw on the way to Bleue mer.
Summary:
Dukh to Shirgegge
20 dt - Bleue Mer supplies
60 dt - Agricultural equipment
1 dt - Speculative Cargo for Bleue Mer
Passengers - Yuppies
Shirgegge to Bleue Mer
20dt - Bleue Mer supplies
60 dt - Animals (though that may not fill the 60dt)
1 dt - Speculative Cargo
Passangers - Vet and animal tender.
That looks like a very sound deal.