I also had some trouble transferring my mouse sensitivity to SC. Since it was never intended to be a true competitive game it is impossible to set perfect settings for the FPS module of the game. It also seems that the games focus is the free movement with zero gravity in space with (vehicle) or without ship (EVA). Sometimes it's hard to understand the design decisions. ...I feel ya, guys.
Dealing with a Rival 110 and the accompanying software from steelseries makes thinks easier as it is possible to set the DPI from 200 to 7200 in steps of 100, what is essential to get to passable sensitivity settings in Star Citizen.
In the game there are different sensitivity instances and multipliers. The foremost is the vehicle/EVA sensitivity (it's the way I call it). There is no switch, no slider in-game for that. It can solely set by mouse DPI and is the "first instance"; this "mode" is active when one is in a vehicle or EVAing in space...everything else builds up on this setting. So the next important sensitivity is the Mouse Sensitivity found in-game in the Controls sub menu. This actually regulates you sensitivity when you are on foot and it is a factor upon the vehicle/EVA sensitivity as signified. The third one is the ADS Sensitivity and is also a factor to the whole. When you aim down sights with a weapon this value regulates how your vehicle/EVA sensitivity combined with your Mouse Sensitivity (if on foot) is readjusted. Yet another factor is the Zoom Multiplier. It manipulates the sensitivity resulting from the factors above furthermore depending on the zoom step when ADSing, especially when some king of scoping is involved. Brain-twister anyone? I skip the Mouse Acceleration and Mouse Smoothing here, sure everyone here is quite familiar with that.
Let's peruse the first person perspective in Star Citizen. When looking around the whole character model is involved. This results in a maximal possible turn speed when EVAing since the suit brings the propulsion for that maneuver. On foot a rotation involves a displacement of the head since the character replaces legs and foots. As I observed it, this happens every 90 degree and than this animation adds some to the rotation caused by moving the mouse! There is are few more interference like this in Star Citizen, but for this thread it is not really of interest.
A little bit more detail about the sensitivity factors and multipliers and how to take advantages of it. As mentioned before the vehicle/EVA sensitivity takes the mouse input as it comes, raw. I did a few measurement series...brute force. Here I got with 300 DPI, 400 DPI and 1100 DPI 27.65 cm, 21.55 cm and 7.2 cm for a 180 degree turn respectively. Next thing that seems sensible is to set the in-game Mouse Sensitivity. With this value one can increase the overall sensitivity if the slider is > 27...28 or decrease the sensitivity if the slider is < 27...28. I settled my DPI at 400 and got 8.75 cm, 19 cm, 23.6 cm with Mouse Sensitivity 100, 40, 29 for a 180 degree turn respectively. As my target is 23.65 cm / 180 turn I went with 29. The next interesting slider ADS Sensitivity decreases the sensitivity identically over all weapons for ADS aiming. It looks like ADS Sensitivity 100 applies 90 % of the overall sensitivity when in ADS, ADS Sensitivity 1 applies about 30 % of the overall sensitivity when in ADS. I set ADS sensitivity to 100. What if one will a fast SMG aim but a reliable aim when scoping with a sniper. This is where the Zoom Multiplier comes in. Depending on the zoom step the sensitivity is further adjusted and every weapon has a zoom when ADSing. All Zoom Multipliers decrease the overall sensitivity, but Zoom Multiplier 1 is in it's effect only 30 % of the Zoom Multiplier 100. Here I go with 1 but it needs adjustments over time.