Practice
Well ive done a weighted version of WC like yours and ive done TST (neutral weight) as well.
To me, its not just about the weight, but the YGKM as well. Keep in mind this stance varies from lineage to lineage and youll find that someone that can do the kick as discussed comes from a taller stance at about shoulder width. TST is a great example of this. It can be done
Im guessing youll have more abducted stance, but lower which makes it harder to do.
Having said that, the back weighted stance allows you to shoot multiple kicks (of the same leg) a lot easier.... i use this in MT to a degree (though stand a lot taller)