Sometimes its not easy for me to pursue this modding endevours and I tend to see less value in what I am doing here. But knowing people are interested enough that they even send donations gives me a really good argument to use to reason my way out from negativity :)
Bad news: with new sitting animations of any type skirt bones just can't stay in place. So I have to put aside cart driver idle project. Until I will have better understanding of this rig I guess.
Good news: retargeting and correcting regular standing idles is very easy! And no skirt bone problems. So I will take a course toward adding new animations to LCA mod and others.