The whole 'strength reduces weight movement penalty' mechanic probably doesn't exist, based on what the developers have stated.
I'd recommend making an STF for testing builds like this. Then you can freely respec that character whenever you want, and get a feel for how you want to build your main. I'd recommend trying a several different builds and armor combinations, before settling on one you like.
You probably already know this, but don't STF your main, or any alts that you have leveled. Just make a new character, and make him an STF.