Infact, 10/4 and 10/3 would probably cover quite a bit of technique imo. Atleast, if you can nail these two, then you have done alot! No where near everything ofcourse, but alot of the usually problem stuff.
What technique is 10/3 about really? I heard it is for legato playing, but is there also other things. I am learning Chopin ballade no.1 now, and want to learn an easy etude on the side. I think I will go for 10/3 since I like this most.