s there no possible way that you could adapt some gate sizes?
Of all the 17 gates on Terminal A, the largest has a radius of 25 mt, some are 22, some 23 and one is 18.
Most heavy airplanes have larger wingspans:
A330/340 = 60.0 mt (parking radius > 30)
B787 = 60.0 mt (parking radius > 30)
A350 = 64.75 mt (parking radius > 32.37)
B777 = 64.8 mt (parking radius > 32.4)
B747 = 68.0 m (paring radius > 34)
I don't know how FSLTL logic works but, if it uses the same as GSX (your wingspan must be lower than double the radius), it shouldn't have placed any heavy airplane on Gates A. Are you sure those you see are placed by FSLTL and not, for example, automatically by MSFS using its own (usually questionable) logic?