Gareths advise is not realistic to follow in your own portfolio. When adding up all his advised current positions, specified in % of total portfolio, the sum at times is waaaaaay above 100%. The reason for this, is that when Gareth has a short position that is down, he keeps adding in hard when the stock pumps, even if the position is 30% or 40% down. That is when one has already allocated 100%+ of the total portfolio, so you are not able to keep up.
Regarding the "verified" return statistics, pay attention to that this shows only closed positions. It does not show you the many open positions that is way down which of some have been open for a very long time.It locks up large portions of your portfolio in bad positions.