Just make a few pieces the correct thickness from LBDs MDF sand to fit then drill mounting holes.
Screw one in place 
Gently  lower the rotating blade at 90 deg and cut the kerf precise ZCI 
this is now perfect for 90 deg and the fitted blade.
If you wanting 45 deg swap it out and repeat for Left and right
You can still use the 90deg one for other angles but it will become wider, but not as wide as Mr Makitas original. 



Regards Rob