Curt basket with 2 extensions creates a full length rack for cheap and has held up fine for 2 years now. You can get away with 1 extension and use the stock crossbars, but I wanted mine low as possible and longer. I bought some aluminum square tubing 1"x 1" and ran it all the way down and drilled holes through the rack and tubing, bolted it down usually the stock square sliders in the rails. Added a couple foot pad for chairs from home depot up front to support the front of the rack
The awnings mounts are from L brackets with pipe U-bolts from home depot.
A side note, 2 extensions will not work with stock cross bars. You will need an additional crossbar and 6 mounts from Curt. Unfortunately, Curt only provides 4 with their rack and I could not track down anywhere to buy 2 additional without buying another rack. Plus Curt's mounts raise it a few inches which I didn't care for.