The good thing about JL audio is the name. Meaning you can start off small and work up, with no problem selling the line you no longer want. I would say if you go with a [email protected]
you should be fine. The wonderful thing about the PG amp you are looking at is that it is 1ohm stable, meaning that if you get bored of 2-10's you can always go with 4-10's for the little extra "thump".
Speaking from experience
HOWEVER, FIRST THING YOU SHOULD DO,
is figure out you are looking for CRAZY BASS, that people can hear down the street then consider going with 12's, but if you like a CLEAN bass (nice and tight) then I would say go with the 12's. If you like dance/techno or metal then I would say either way you would really have to go with 10's, but if you like hip/hop, r&b or reggae you could get away with 12's. I listen to everything, but I love CLEAN BASS, with balanced mids/high's so I would still say go with 2 10's and then work your way up to 4.
Just an idea,