First off, congratulations on the accomplishment.
I can't really answer you first question, but as far as the second question, practice is the main thing. With your wedges you should have three different distances. Three different swing lengths with your wedges will help do this. With lots of practice, you should be able to develop and become consistent with these distances.
The best thing to do when it comes to knowing which lofts you should have, find out the loft differences between your 8i-9i-PW, then depending on those differences, you should be able to determine the differences in loft for you wedges.
If your PW is 120, three other wedges with three distances for each, will give you nine different distances inside that 120, this does not include the two other distances you should be able to come consistent with with your PW.
Wedges are a all about the practice. Best of luck with them.