Here are a couple of things to remember about bits: It is a myth that a bit with a curved shank has more leverage value than a bit with a straight shank.  A straight up and down shank has the same leverage as a curved shank.
People say,  “My horse loves this or that bit.”  The truth is that you love the way your horse goes in that bit,  your horse would just as soon be out in the pasture eating grass.

When evaluating a bit take into consideration the combination of mouthpiece and rings or cheeks,  as well as  the rider and horse doing the shopping.  You’ll learn from every bit whether it’s perfect for your horse or not – and keep experimenting.  Bits are like horses;  one is never enough! 

Les Vogt's Silver Bits Form To Function Bitting System uses special combinations of mouth pieces and cheek pieces to give you perfect leverage, flexibility, and balance to maximize every horse's performance.   
Bit Leverage Position #1  For short-necked horses with low neck set that need some lift at the poll to flex properly and re-distribute weight to the hindquarters.  
Bit Leverage Position #2  Gives the classic-necked horse the performance advantages of perfect neck flexion and head position.   
Bit Leverage Position #3  For horses with higher neck and head carriage. Designed to lower high neck and head giving that soft flexion needed to increase performance.