Chemical RCS and attitude control

Make me kill the astrogators, or kill me.

Problem: My NTR refuses to work as main thruster. They don't accelerate me in tactical map, want to fight with my RCS.

Below is craft blueprint in rather simple look

CraftBlueprint PCC Zweihander
   Description
       PCC-01 Zweihander: Nameship, aremed with Autofire railgun
       PCC-02 Claymore: Minor modification
       PCC-03 Executioner: Aremed with Broadsider railgun
       PCC-07 Glaive: Equipped with better engine, has decent TWR for tactical dodging
   Modules
       60.4 MW Thermoelectric Fission Reactor 2 -0.375 null 0 0
       60.4 MW Thermoelectric Fission Reactor 2 -0.125 null 0 0
           100x20 Silicon Carbide Radiator 1 56.848 60.4 MW Thermoelectric Fission Reactor 3.1416 0
           100x20 Silicon Carbide Radiator 1 77.192 60.4 MW Thermoelectric Fission Reactor 3.1416 0
           40x10 Silicon Carbide Radiator 1 29.537 60.4 MW Thermoelectric Fission Reactor 3.1416 0
           40x10 Silicon Carbide Radiator 1 39.565 60.4 MW Thermoelectric Fission Reactor 3.1416 0
           40x10 Silicon Carbide Radiator 1 92.764 60.4 MW Thermoelectric Fission Reactor 3.1416 0
           40x10 Silicon Carbide Radiator 1 103.5 60.4 MW Thermoelectric Fission Reactor 3.1416 0
       20.0 m Diameter Polyethylene Radiation Shield 1 32.343 null 0 0
       6.05 km/s Methane NTR Low Gimbal 2 0 null 0 0
           600 t Methane Tank 2 32.558 null 0 0
           600 t Methane Tank 2 33.634 null 0 0
       2.67MN Methalox Combustion RCS 2 6.3802 null 0 0
           30.0 t Oxygen Tank 2 122.45 null 0 1
           30.0 t Oxygen Tank 2 53.165 null 0 2
           30.0 t Oxygen Tank 2 70.233 null 0 3
           30.0 t Oxygen Tank 2 103.2 null 0 4
           30.0 t Oxygen Tank 2 31.785 null 0 5
       35 Crew Module 2 33.096 null 0 0
           10x4 Silicon Carbide Radiator 1 22.207 35 Crew Module 3.1416 0
       13.0 MW 5mm Broadsider 1 56.659 null 0 0
       13.0 MW 5mm Broadsider 1 59.033 null 0.34907 0
       13.0 MW 5mm Broadsider 1 59.033 null 5.9341 0
       13.0 MW 5mm Broadsider 1 64.52 null 0.34907 0
       13.0 MW 5mm Broadsider 1 64.52 null 5.9341 0
       13.0 MW 5mm Broadsider 1 66.301 null 0 0
       13.0 MW 5mm Broadsider 1 80.756 null 0 0
       13.0 MW 5mm Broadsider 1 84.518 null 0.34907 0
       13.0 MW 5mm Broadsider 1 84.518 null 5.9341 0
       13.0 MW 5mm Broadsider 1 89.454 null 0.34907 0
       13.0 MW 5mm Broadsider 1 89.454 null 5.9341 0
       13.0 MW 5mm Broadsider 1 92.631 null 0 0
       13.0 MW 5mm Broadsider 1 107.1 null 0 0
       13.0 MW 5mm Broadsider 1 109.06 null 5.9341 0
       13.0 MW 5mm Broadsider 1 109.06 null 0.34907 0
       13.0 MW 5mm Broadsider 1 113.93 null 5.9341 0
       13.0 MW 5mm Broadsider 1 113.93 null 0.34907 0
       13.0 MW 5mm Broadsider 1 116.55 null 0 0
           100000x 10mm Railgun Round 18 -0.6875 null 0 0
       Fire Control System 1 86.354 null 0 0
   Armor
       Shape Hexagonal
       Concave true
       AspectRatio 2
       ArmorLayers
           Para-Aramid Fiber 0.0075 0 0 1 1 0    
           Graphite Aerogel 0.2 0 0 1 1 0
           Boron Filament 0.05 0 0 1 0.4 0.8
           Graphite Aerogel 0.2 0 0 1 1 0
           Aramid Fiber 0.003 0 0 1 1 0
           Fused Quartz Fiber 0.003 0 0 1 1 0
           Graphite Aerogel 0.2 0 0 1 1 0
           Tin 0.003 0 0 1 1 0
           Diamond 0.001 0 0 1 0.4 0.8

I tried to look at this if they contain any marker like "this is RCS or something but found nothing.
So...how can I tell this mental game "Hey, this is not main thruster"?
I tried anything as far as I can imagine: re attaching RCS, making NTR no gimbal-able, etc.


Below is downloadable craft file: here