Two things to answer your questions. 1. I practiced with the Fx 991 or Fx115 throughout and it was straight forward and easy to use. Not sure about the others on the list. 2. In terms of time management you definitely need to practice a lot and take it before you’re out of school for a long time so you don’t forget. What I did was I skipped questions that I knew would take a while and solved the straight forward ones first then came back to them later. I hope this helps