I think it would be helpful to add vocabulary list in every HSK exercises like you do it in the ordinary lessons and also do it possible to launch flashcards with it. First of all the HSK lessons are already devided into different levels so it would be easy to find out what words are unknown for the people of specific level. If a person did the test then learnt vacabulary from it like about 10-20 new words it would be more effective than when you open that huge HSK vocabulary list and just don't know from what to start because some words you already know and some not. Just feel rather confused.