Try Wc51 + Rifle
Are you kidding? I have been using the WC51 many many times on every modes from 1vs1 to 4vs4 and won many early game because it, I promoted it during months last year.
The reality is today a WC51 can´t do shit vs x2 or x3 kubels push with a SP in the middle. It is simple mathematic.
1SP + 3xkubel >>> 1xRE + 1xWC51 + 1xRM, even if you put your RE in the dodge to maximize your dps vs the kubel.
They just need to focus fire the WC51 from long range.