Dal, if you still want to determine the CG of MAC for your loaded aircraft, follow my guideline, it is pretty easy, you need a little time to do it. The formula is in the internet.  Google " CG of MAC "

First find the chord of MAC for the airplane you are working with.
Use a Boeing graphic to find the lenght of wing panels, position of stab
for calculation. blow up the graphic and scale measure the distances.

Next the datum line, go to the aircraft.cfg find 'ref_datum_position"
the numbers could be 0.0, in such case Microsoft in its definition of the file says 0.0 is equal to the front edge of the leading edge of the wing.
Each weight added sits a a distance from the datum line ( the arm)
watch also the lateral distance to load equal on each side. You could fly with a low wing.
Work the moment of each item.  and including the aircraft empty weight
moment and the distance to the datum. Fuel !
remember that the weight of passenger varies with country of departure and season.
add up all the moments + or minus / total weight of aircraft.
this will give you the CG. Transfer it to the MAC chord and see if you are within the range.
I dont do that !
I rather fly !
This is what I do. take the 57, add your payload. Make the cargo a little light at the back. Take a little over 9000lbs of fuel - your expected landing fuel - the reserve.
Take off and come back to land. In full landing config at the treshold at the proper Vref speed, the attitude of the plane should be 1 or 2 degrees nose up. Your CG is set right. If not, move cargo weight until you get it.
Recently I though my 67 when landing, the nose wheel was coming down a little too quick, I added 300 lbs in my bulk cargo at the back'
Now I get 2 to 3 seconds before the nose come down.

Dal, Happy flying  ;)

Raymond   boeing or nothing
KFLL   South Florida