Hi! I recently bought a used Sling Blade as my first "serious" ball.  A couple days later I bought a new Big Blue, both of which are 15 lbs.  I don't know anything about drilling, but I do know that both are drilled pretty agressive according to my driller (Mike Riggins).  He told me all the stats...but I really don't understand the lingo yet.  I am starting to pick up on it though.  

So, now that I have a Sling Blade and Big Blue, what do I need to complete a 3 or 4 ball arsenal?  Any suggestions? Thanks.