Clouds do work, lightning does not. The Kessil A360W is such a great light -- it's even better when controlled by the Apex.
Believe it or not, while cloud cover seems silly, I have a couple virtual outlets programmed on my Apex and use it when acclimating new corals. Works really well.
A good starting point/example Apex VDM outlet config is below -- keep in mind you MUST setup the profiles associated before the outlets will work properly. If you plug in to the V1/V2 port your V1 outlet is the color channel and V2 is the intensity channel. This is not my exact code but what I used to get started.
Profile Name: Int_Sunr (sunrise)
Control Type: Ramp
Ramp time (minutes): 60
Start intensity: 0
End intensity: 55
Profile Name: Int_Dayl (mid-day)
Control Type: Ramp
Ramp time (minutes): 1
Start intensity: 55
End intensity: 55
Profile Name: Int_Nigh (sunset)
Control Type: Ramp
Ramp time (minutes): 60
Start intensity: 55
End intensity: 0
Profile Name: ColorDay (DayTime)
Control Type: Ramp
Ramp time (minutes): 1
Start intensity: 40
End intensity: 40
Profile Name: ColorRise (sunrise)
Control Type: Ramp
Ramp time (minutes): 60
Start intensity: 60
End intensity: 40
Profile Name: ColorSet (sunset)
Control Type: Ramp
Ramp time (minutes): 60
Start intensity: 40
End intensity: 20
V1 outlet:
Set OFF
If Time 14:00 to 15:00 Then ColorRise
If Time 15:01 to 22:00 Then ColorDay
If Time 22:01 to 23:00 Then ColorSet
V2 outlet:
Set OFF
If Time 14:00 to 15:00 Then Int_Sunr
If Time 15:01 to 22:00 Then Int_Dayl
If Time 22:01 to 23:00 Then Int_Nigh