My three rear plates, Radar HRT on the right. Half boot hardshell, half boot semi hard and HRT. The semi hard and HRT have bungee laces. All three work equally well for me. I am most comfortable with buckles instead of laces, personal preference. But after using double boots forever, I changed and agree, I ski better without the full rear boot.
I use a very low cut liner in the two shells to free up my rear ankle movement.