Im guessing that you want them to slowly ramp to that value to simulate sunrise and sunset right? You just want max intensity at 20% so you can work them up to full brightness?
If so, create 3 profiles. If you want different amount of red vs blue, you can make 3 more and change intensities accordingly
RampUp
Type: ramp
Ramp time: 120
Min intensity: 0
Max intensity: 20
RampDown
Type: ramp
Ramp time: 120
Min intensity: 20
Max intensity: 0
Day
Type: weather
Max intensity: 20
Cloudy intensity: 15
Cloud duration: 5
Cloudy time: 5
Prob of lightning: 0
Lightning intensity: 0
Light_V1
Set OFF
If Time 07:00 to 09:00 Then RampUp
If Time 09:00 to 19:00 Then Day
If Time 19:00 to 21:00 Then RampDown
As you acclimate, just slowly increase 20 by 5 each week until you hit a sweet spot. I like to set my cloudy around 80% of my max intensity so its still apparent, but not too dim.
You might be an engineer if...You have no life, and you can PROVE it mathematically.