You can get all types, I use the ones with slightly bigger holes. You don't need to buy some expensive LST shelf unit when you can spend a few bucks and have the same thing, with a little elbow grease.
Im using that too right now and I dont really like it. Previously I was using a section of fence with 3" square holes, and I'll be going back to that next crop.
Make yourself a picture frame, go out and get you some weed eater twin, use that to make your grid and use drywall screws to hold it. Its a hard plastic so drywall screws work good.