Greetings,
I welcome your commitment with the B-52

But, first of all, optimations in the Flight Dynamics are very difficult to change because the core of the FD are in the *.air file.
For me, I have taken the changes here in the forum and found a compromise between the mod and the Original. The problem is the correct (max) Speed and AOA while curising. If you use the FD-Mod found here as is, the speed is too low and the AOA too high. Takeoff and Landing with this Mod is ok, but I don't like the high AOA and low (unrealistic) speed.
If you would try my settings, here are my settings in the aircraft.cfg:
[WEIGHT_AND_BALANCE]
max_gross_weight = 488000
empty_weight = 183535
reference_datum_position = 0, 0, 0 // (feet) distance from FlightSim Reference position: (1/4 chord, centerline, waterline)
empty_weight_CG_position = -7, 0, 0 // (feet) longitudinal, lateral, vertical distance from specified datum
max_number_of_stations = 50
station_load.0 = 168.0, 64.5, -2.0, 8.0 //Weight (lbs), longitudinal, lateral, vertical positions from datum (feet)
station_load.1 = 170.0, 64.5, 2.0, 8.0 //Weight (lbs), longitudinal, lateral, vertical positions from datum (feet)
//station_load.2 = 354.0, 0, 0.0, 0.0 //Weight (lbs), longitudinal, lateral, vertical positions from datum (feet)
station_load.2 = 354.0, 60.5, 0.0, 8.0 //Weight (lbs), longitudinal, lateral, vertical positions from datum (feet)
station_load.3 = 0.0, 0.0, 0.0, 0.0 //Weight (lbs), longitudinal, lateral, vertical positions from datum (feet)
station_name.0 = "Pilot"
station_name.1 = "Co-Pilot"
station_name.2 = "Crew"
station_name.3 = "Internal Weapons"
;Moments of Inertia
empty_weight_roll_MOI = 13352310
empty_weight_pitch_MOI = 24223159
empty_weight_yaw_MOI = 39531785
empty_weight_coupled_MOI = 0
[fuel]
//Tank, Longitudinal (feet), Lateral (feet), Vertical (feet), Usable(gallons), Unusable (gallons)
LeftAux = -14.0, -52.14, -6.8, 4905.0, 6.0 //No. 1 Main
RightAux = -14.0, 52.14, -6.8, 4905.0, 6.0 //No. 4 Main
LeftMain = 5.6, -25.68, -4.3, 6834.0, 25.0 //No. 2 Main
RightMain = 5.6, 25.68, -4.3, 6834.0, 25.0 //No. 3 Main
LeftTip = -31.46, -78.9, -8.9, 1051.0, 7.0 //Left Outboard Wing
RightTip = -31.46, 78.9, -8.9, 1051.0, 7.0 //Right Outboard Wing
Center1 = 16.4, 0.0, -12.3, 2053.0, 4.0 //Fwd Body
Center2 = 7.2, 0.0, -12.3, 3458.0, 12.0 //Center Wing
Center3 = -6.7, 0.0, -12.3, 15500.0, 21.0 //Mid + Aft Body
External1 = -23.0, -77.3, -11.5, 700.0, 5.0 //Left External
External2 = -23.0, 77.3, -11.5, 700.0, 5.0 //Right External
[flaps.0]
type = 1
span-outboard = 0.8
extending-time = 60
flaps-position.0 = 0
;flaps-position.1 = 10
flaps-position.1 = 20
;flaps-position.3 = 29
;flaps-position.4 = 30
;flaps-position.5 = 31
;flaps-position.6 = 32
;flaps-position.7 = 33
;flaps-position.8 = 34
flaps-position.2 = 35
damaging-speed = 250
blowout-speed = 270
//lift_scalar = 1.0
//drag_scalar = 1.0
//pitch_scalar= 1.0
lift_scalar = 0.5 //0.58//0.75//1.1
drag_scalar = 1.2
pitch_scalar= 1.2 //1.5 last
system_type = 1 //Hydraulic
[flight_tuning]
//cruise_lift_scalar = 1.0
//parasite_drag_scalar = 1.0
//induced_drag_scalar = 1.0
cruise_lift_scalar=1.0 //1.5 last worked
parasite_drag_scalar=1.0 //1.7 last worked
induced_drag_scalar=1.0 //1.8 last worked
elevator_effectiveness=0.7
aileron_effectiveness=0.4
rudder_effectiveness=1.0
pitch_stability=1.0
roll_stability=1.4
yaw_stability=1.0
elevator_trim_effectiveness=1.0
aileron_trim_effectiveness=1.0
rudder_trim_effectiveness=1.0
[GeneralEngineData]
engine_type=1 //0=Piston, 1=Jet, 2=None, 3=Helo-Turbine, 4=Rocket, 5=Turboprop
Engine.0 = 20, -60, -10
Engine.1 = 0, -34, -8
Engine.2 = 0, 34, -8
Engine.3 = 20, 60, -10
fuel_flow_scalar = 0.80 //Scalar for fuel flow efficiency
min_throttle_limit = -0.50; //Minimum percent throttle. Generally negative for turbine reverser
[TurbineEngineData]
fuel_flow_gain=0.002 //Gain on fuel flow
inlet_area=16.00 //Square Feet, engine nacelle inlet area
rated_N2_rpm=29900 //RPM, second stage compressor rated value
static_thrust=30000 //Lbs, max rated static thrust at Sea Level (2X 14550)
//inlet_area=17.0
//rated_N2_rpm=29920
//static_thrust=30000
afterburner_available=0 //Afterburner available?
reverser_available=0 //Thrust reverser available?
ThrustSpecificFuelConsumption=0.52
[jet_engine]
thrust_scalar=1.0
As you see, this is not the whole aircraft.cfg, you have to copy and paste the sections in question.
I also modified the Flaps: Now there are only 2 Positions: 50 % and Full. The sections between are not needed for TO and Landing. This saves time and nerves

And your answer for your 2. question is also in my cfg as above. I think this is the correct amount of fuel as you can see at, eg. wikipedia.
I hope this helps, I know the FD are not 100 % accurate, but for me it is ok and it is better than the original.