I had about 2000 lbs of 2 X 4s and 2 X 6s to store on a rack on a concrete block wall at the back of my yard (home).
I bought TWO SETS (2 racks each) of the lumber racks. There were simple, but... not fun to assemble the arms on the vertical square tubes. Each one required a device to stop them at their new level and it took a while.
Then when it came time to screw them to a concrete block wall, (( fortunately had the blue concrete screws, the correct length, because Grizzley does NOT provide them!), it was another chore to insert each screw AND the plastic spacer behind it!
All that said, I used my handy Ryobi hammer drill to drill holes into the concrete block wall, using the vertical post pieces of the Grizzley product as a guide/ template. That worked great.
Then I hung each (4) of the grizzley racks up, held by one hand, as I inserted a concrete wall blue screw through the top hole, just to hold it straight. I used the holes in the Grizzely form as a guide for drilling the other holes, followed by the spacers and screws.
I'm quite happy to say, I REALLY LOADED UP the racks with FULL load of lumber! There is no more room for any more 2/X4 or 2X6 boards! It holds the weight!
I had sloppy wooden lumber racks I made myself out of 2X4 many years ago. They worked OK until every storm, hurricane, snow, etc, hit us here in Las Vegas. I was contemplating replacing with some sort of racks I made myself. Glad I didn't. At their price (Grizzley about $26 per pair of racks?) no one can beat them. Buy a pair, or... as I did, buy4 each (2 pair) and have at it!