I just installed E track in my enclosed bike trailer. I would not use screws. I used 1/4 in bolts with flat and lock washers. May be overkill but i dont want to open the trailer to a pile of bikes. I put a bolt every 4th hole so i skipped two unless it hit on a crossrail then i put one in it too. I layed it out drilled the holes and got a buddy to hole the bolts while i installed the washers and nuts and tightened them up. The bikes weigh 500-800lbs and i compress the suspension when towing and try to use a spot where it has a bolt.