Was strange watching that video, firstly both the stations on 385 and 375 at start are both from my home city Glasgow, I know that accent anywhere.
The guy that made the video doesn't understand AM watts too well, often referred to the carrier as x amount of watts avg rms. you don't get watts rms, you get Avg watts, which comes from the rms of voltage and rms of current multiplied.
20 amp draw is about right for a 140-160w radio depending on bias/amplifier class and wires sufficient to reduce voltage drop to next to nothing. No way is 20 amp going to do 500w, even with 100% efficiency it would struggle around 260w.
108" whip would be ideal and was the length they were always made too allow tuning all over cb band with a bit of trimming. Usually about 104-106" is about right depending on where you centre it.
Normal vswr should be just under 1.4:1 at resonance, about 36 ohms, but there's a few factors in that and may well read higher or lower depending on situation and surrounding materials. A vswr of 1.39:1 is insignificant and adding a lossy shunt coil to tune it out seems self defeating. Will still blow the arse off every 50 ohm mobile made, despite any manufacturers claims of audio gain or shite like that.
a resonant dipole has a slightly higher vswr at 72 ohms in freespace,approx 1.44:1, again no biggie, again dependent on mounting location and surrounding objects. I don't see many rushing out to shunt coil their dipole despite the vswr being worse.
I don't see what claims Robb made you have issue with.
I fail to see the point in custom cb's. if you need it customised you bought the wrong radio, All a good radio should need is a good alignment if its not already aligned well. A half decent export with a rm kl203p will do the job worldwide. And biggest advantage of all is if radio or amp blows you still have the other to use whilst the faulty part is replaced, put both in one case you lose the lot. Plus add extra heat, the biggest enemy of most of these radios for stability.
All that money too murder any advantage you would gain by using a wilson or k40 seems pointless when a sirio or 1/4 wave whip are both cheaper and more efficient than either.