The Two-Gimbal Ducky uses only the 2 gimballed thrusters for all control. The vehicle only accelerates forward, and can only pitch. roll, and yaw as a result of the thrusters gimballing. This means that forward thrust must be applied for the vehicle to accelerate on a rotation axis.
As with the other vehicles, rotation assist makes use of the vehicles thruster array, therefore rotation assist also has these same limitations.
I will soon add the Two-Gimbal Hopper full version, and MAY include one more vehicle as part of the "Simple Vehicles Update". The "Simple Vehicles Update" is made of a set of vehicles that do not have a full-featured thruster array, and are built around making use only of a gimballed thruster. The final vehile which may be added or may be added later , will be one that rather than using gimballed thrust, will use "thrust vanes" mounted in the thrust plume. The difference in feel while flying this craft should be greater reduction in forward thrust during rotation input, as the vanes will result in drag in the thrust plume.
Although the full features are already available for several of these vehicles as a result of small updates, the "Simple Vehicles Update" will be an official point of completion of these "Simple Vehicles". The next step for vehicles to be included will be a "Full Thruster Array" set of vehicles which will make use of gimballed thruster or vectored thrust thrusters, while being paired with a normal 6-axis RCS array. These vehicles will also feature a set of input options, where the vehicle can be controlled using an algorithm that makes use of all available thrusters and depending on player input it will automatically determine to use the gimbals or rcs array for those rotations that can be done with either, or alternatively the RCS array can be assigned separately from the gimbal actions (which may require up to 10 axis for input) allowing the player to use various thrusters as they see fit depending on the given maneuvering circumstances.
Estimated timeline for this full featured thruster update is unknown, although I expect it to take a few months in total. As features are built they will become available in small updates, but I will focus first on completing all of the simple vehicles first, and likely a reorganization of the menus. I also may try to include additional "training content" although this is not a priority as the vehicles are already challenging enough that a "walkthrough of controls" will not result in player success anyway. The vehicles must be practiced regularly, therefore training content will be limited to simple course elements arranged for players to have access to easily accomplishing basic navigation once they have learned the controls on their own. (there is a controls description already included in the menus)