I'm more concerned about plant growth than algae wars

Running the lights too long is bad for plants.
Less is wiser than more.

Sunlight certainly exacerabtes GDA, even causes it IME/IMO in some tanks.
Clean tanks often get it, powercompact users, never have gotten in a HQI MH's tank before.

Oh it's there and all, it just never grew.

I think if someone wanted to, they could kill it by doing the 4 day blackout + Excel overdosing(1.5X) with daily 80% water changes and glass wipes+ adding EI nutrients back each time.

That should knock back most any algae pretty good and not cause any issues for plants.

From there, make sure good CO2/nutrients, 10 hours of light etc water changes, no direct sunlight etc.

Regards,
Tom Barr