Firstly, thanks for your interest in our strategies!
The 2x leverage in the portfolio builder is actually only simulating the leverage you would apply in your account. For the signals it is indeed a straight forward multiplication, but the portfolio change a bit due to underlying trading costs and different math when combining strategies. So, yes, it would be up to you applying the X times leveraged signals in your account.
We have no real experience using CFD’s as this is not needed when playing “safe” with max leverage of up to two times. Also we would not use them due to higher transaction costs (as you rightly point out) and them performing different than plain vanilla ETFs. Leverage is a dangerous game even using standard ETF, and even more when using leveraged ETF, this is why we do not advise any subscriber to excessively leverage or use exotic instruments.
Hope this does not discourage you, glad to further discuss,
All the best,