I've gotten to single digit body fat on a number of occasions before.
The Velocity diet works. Very well. It looks like a lot of protein powder to take, because it is.
However you don't feel very hungry and you get to taste sweetness every day without eating carbs.
RFL is, if I remember correctly, only intended to be run for a couple of weeks at most. Also I'm pretty sure Lyle did not recommend lifting whilst running the diet because of how energy depleting it is.
Carb cycling has been the most effective method for me, it won't work unless you're lifting heavy at least 3 days a week, thereby justifying the high carb days.
The real answer though, is probably not the one you want to hear:
Losing lots of weight in 30 days is not the way to do things. Make sure you eat well and exercise regularly all the time. If you carry a decent amount of muscle you won't look terrible when you take your shirt off, even if you're carrying some extra body fat.
Building muscle however, takes time. Which is why you see way more skinny people than muscular people walking around.