Changing Sphere Reflection Brightness in Blueprint

I created an outdoor night scene that smoothly changes the directional light and skylight intensity to zero after dusk, using a float curve. The scene also contains a sphere reflection capture that works as expected during the day.

However, at night the reflection capture ‘lightens’ reflective objects in the scene so they are unnaturally visible at night. This can be resolved by setting the sphere reflection capture ‘brightness’ to zero which fixes the issue.

The problem is, I now want to set the sphere reflection capture ‘brightness’ value from 0.0 to 1.0 from within
the level blueprint along with the dir and sky lights but there doesn’t seem to be a ‘Set Brighness’
option in the variable list.

Is the ‘brightness’ parameter of a sphere reflection capture accessible by another route?

Fyi, I don’t want to darken the objects by using a higher post process ‘exposure’ as that will adversely
affect other subtle lighting.

Alternative hacky method:
There is a ‘set influence radius’ variable listed if I untick [ ]context-sensitive-search on a SphereReflectionCapture ref
(dragged into a level blueprint), but it is not compatible with the ref. When or how can the Set Influence Radius variable be used?

If I drag a wire off the SphereReflectionCapture reference I dropped into
my level blueprint I can access a
[Capture Component]. There is a ‘Get Brightness’ variable …but no ‘Set Brightness’ counterpart. grrrr !

you can’t change brightness at runtime But a workaround is to change the AO in the material at runtime. Ao = 1 → no reflection

Thanks.
I solved my issue last year by rebalancing the scene lighting, but your AO suggestion may still come in handy for other situations, so noted.