I did install it on our stock Tundra and 179. I used 4 spacers and installed the L brackets on the tongue in the lowest position. I also bolted the head of the hitch in the lowest position on the stock shank. Having the hitch higher and/or more spacers and/or having the the L brackets higher resulted in the Tundra being a bit nose down from the instructions provided by Fastway. With this set up when sitting on flat ground the stance of the TV is good and the Rpod is slightly nose down (about 1 inch measuring from the front and back of the frame to the ground).
I know that Fastway indicates that 5 spacers are the minimum but that didn't seem to work for me. I can't see any problem with 4 spacers. One caveat. I did this shortly after we bought the trailer and it wasn't fully loaded. I will check the setup again later this year and adjust if necessary.
I'm happy with the results.