Update to this: I just vaulted to Lieutenant.
Tun turned out to be great for rank progression. Went from 24% Ensign to 14% Lieutenant yesterday.
Nice to have Tun so close to my base of operations (3 jumps from Nanomam).
Going to add a commentary on taking full advantage of Tun's location, and what one might want to have "on board" when you go there to rank grind.
Tun will have several missions that do not require any travel at all if one pre-loads your cargo hold with the following items: Agri Medicines, Basic Medicines, Progenitor Cells, Performance Enhancers, Non-Lethal Weapons, and Reactive Armour.
If you also have room for some food stuffs like Coffee, Tea, and Fish load a few units of each. -These because while Tun is Agricultural; it does not produce very many units of those foods.
I mention all these because Tun issues Missions (in addition to the "Give us a Handout" Missions) that ask you to acquire either Food or Medicines.
If one has any kind of cargo capacity, having a hold full of these items will open up a few more easily completed Rank Missions.
It has been a huge benefit for me using Tun as a grinding location: It's three jumps from LHS 215 (My shipyard. One jump from Nanomam), and Nanomam (Zack Hudson's Capital).
(Spring Orbital in LHS 215 produces many of the Meds, and Weapons one needs to take to Tun fyi).
Yesterday was a good day: Went from 14% Lieutenant to 19% Lt. Commander...while washing the dishes, tuning a friend's bicycle, stripping one of my bicycles for re-painting, drinking BEER etc etc...
Oh, and don't forget to jump from Private/Solo to Open and check the Bulletin Board for extra Missions!