I'm looking to move on up to a six string soon and I just so happen to be a very indecisive person. 
I don't have many chances to try out six string basses (I've actually only have had the chance to play two different models) so I'll be most likely buying with my eyes closed in this situation.
I have looked at basses with a range of features and come back to the same three
1.) Ibanez BTB776PM
2.) Ibanez SR506 (Its one of the two I have played, the other being a yamaha trb1006)
3.) Schecter stiletto studio 6
I really dig the neck shape or profile on the two sixes I've played. (Where its not a "C" shape perfectly but has more thickness near the heavier gauged strings)
My first, really novice, question is: Do all sixers follow the same profile I described? Second, Which bass do you prefer?
Thanks in advance for any knowledgeable input in my situation

I don't have many chances to try out six string basses (I've actually only have had the chance to play two different models) so I'll be most likely buying with my eyes closed in this situation.
I have looked at basses with a range of features and come back to the same three
1.) Ibanez BTB776PM
2.) Ibanez SR506 (Its one of the two I have played, the other being a yamaha trb1006)
3.) Schecter stiletto studio 6
I really dig the neck shape or profile on the two sixes I've played. (Where its not a "C" shape perfectly but has more thickness near the heavier gauged strings)
My first, really novice, question is: Do all sixers follow the same profile I described? Second, Which bass do you prefer?
Thanks in advance for any knowledgeable input in my situation