Hi friend,
For the light intensity, one SF2000 light is enough for the 2’X4′ tent.
But if you want to use two SF2000 in the 2’x4′ tent, their size is just suitable. The size of one SF2000 is 25.51*10.55*2.32INCH.
If you want to use a bar light in the 2’x4′ tent, you can also consider the G4500. Its core coverage is 2FT*4FT and its max coverage is 3FT*5FT.
Hope this is helpful to you. 
+3
