T5 hybrid with Radion G1 TIR

[Gomery12]

I currently have a Radion G1 with TIR lenses. I want to make a hybrid combo with T5 Retrofits into a canopy. I have a 36 inch long tank and 24 inch width, water depth ends around 18 inches. Question for the retrofit, is I believe that 2 of the 24w (24 inches) would work and think the next up would be overkill length up would be overkill. Anyone else use a hybrid on a 36 inch tank? Thoughts? Should the length of the T5 equal tank length. My aquascape won't be 36 inches. Probably 25-28 inches.
My tank is a 57 g rimless Oceanic Illuminata.