Buggy leafs and double shackles both carry the same issue with unloading. Ive seen buggy spring setups out flex 4 link but they lack the control of 4 link on extreme angles. Its why most buggies use 4 link. One nice thing about both buggy springs and dual shackles is you can make a bracket to lock them in place so when your on the street you wont get your ass end jumping around.
Tho Like Pat said above if you dont have the weight on the axle its not gonna get the best traction. It is easy to add weight to an axle to help this.
