This might help explain what I was thinking about:
IF I decide I need a speed brake, my cowl flap will be a little longer and extend beyond 60 degrees.
The whole idea is to increase drag so the plane will descend at a steeper angle. But this is not something I have to do in the first version other than to make sure the linkage supports a larger extension. If the plane needs more drag, a longer replacement and/or a perforated plate (aka., SDB dive bomber) will work.