You need 2 drivers.
The strips are 38.9mm wide so c channel of 1 and 3/4" = 44mm will do.
Now double check and measure the 4’x4′ space, you may not quite be able to fit 4’ strips – even though these strips are not actually a full 48” long, they may be a tight fit by the time you incorporate your frame (if you’re growing in a tent) so be sure to measure your space to ensure they’ll fit first!
If it dont fit you can use 2ft f strip build instead.