You can add this line to the effects section of the DR_MS406_AX675.XDP file to have the appropriate dynamic gunsight.
<Effect Type="Track" EffectName="FR_OPL_4_gunsight" PosX="0.000" PosZ="-1.066" PosY="1.22" Pitch="90" MinVel="-999999" MaxVel="999999"/>
p.s. In the category of it's a small world I noticed a Scintilla data plate on the dash panel of the MS.406. Back in the late 80s I worked in the Amphenol Bendix plant in Sidney, NY making electrical connectors. The old timers there told me the history of the place starting with automobile assembly around WWI and then switching to magnetos. During WW2 it made almost all of the magnetos used by our Allison powered military aircraft (>150,000). The company name had been... Scintilla.