I am trying to do something similar - to lower the gunsight and obviously the line of fire accordingly to line up with a Spitfire's Reflector gunsight reticle. My existing settings are:
<WeaponInfo>
        <!-- aircraft dependent weapon settings -->
        <Weapon>
            <!-- weapon sub-type section. unlimited number of -->
            <Gun>M60C</Gun>
            <!-- weapon sub-type name. must match GunInfo>Gun>Name -->
            <Shell>M60C Bullet</Shell>
            <!-- shell name. must match GunInfo>Shell>Name -->
            <Unlimited>1</Unlimited>
            <!-- unlimited ammo fire. 1-yes, 0-no -->
            <Station name="Left Wing Outer" params="-4.0,0,-0.5,0,-0.017,0,200" />
            <Station name="Left Wing Inner" params="-3.0,0,-0.5,0,-0.017,0,200" />
            <Station name="Left Wing Middle" params="-2.0,0,-0.5,0,-0.017,0,200" />
            <Station name="Right Wing Middle" params="-2.0,0,-0.5,0,-0.017,0,200" />
            <Station name="Right Wing Inner" params="3.0,0,-0.5,0,-0.017,0,200" />
            <Station name="Right Wing Outer" params="4.0,0,-0.5,0,-0.017,0,200" />
            <!-- Station position (x,y,z) meters, angle of incidence, ammo units quantity -->
            <Mode name="AUTO" shotrate="10" setshots="0" sequence="1+2+3+4+5+6" />
            <!-- fire mode section. unlimited number of. name= dispayed on HUD in weapon info string. -->
            <Mode name="X10" shotrate="10" setshots="10" sequence="1+2+3+4+5+6" />
            <DefaultMode>AUTO</DefaultMode>
            <!-- default fire mode. Any from the list above  -->

How do I lower the aiming point?

Thanks


Mike