I think people get to carried away with all this talk of forward and back testing. You are making it more complicated than it needs to be. Simply put; you need to explain logically why doing what you intend to do will work, and most importantly why it will work in all market conditions.
If you can be precise about this you need to do neither; forward or back test.
Traders get the best results by being logical, not systematic. Systematic = restricted, whereas logical = evolving.
Here we go again, another one of the brigade where there's only one way of doing anything, namely his way!
This trait is usually universal in novice traders who've just found a way to make a bit of money in the markets (often flawed anyway). Not saying WW87 is, but it seems to be a common denominator for others.