I am a newbie too but I think Junior is better than primary and yes you can get results of primary if you had used junior and third one I only know +1 to +3 they are basically the success rate if i am not mistaken (sorry but some have to check this) but i always use +1 to +3 when compounding +4 and up are rare ... (when i say rare you'd have to do a few times before you get the result) unless you have book to support

Primary Alchemy:

max. Uprank: 3 + Books = max +7

Junior Alchemy :

max. Uprank: 4 + Books = max +8

uperior Alchemy:

max. Uprank: 5 + Books = max +9

and for complete little intro for compounding I find that Osoko's guide (for me) the simplest to understand http://forum.wl.igg.com/viewthread.php?tid=82674