Dont rely on counter help being nowledgeable, most places are nothing more than a revolving door nowadays.
I remember back in the mid 90s, a lot of us hot rodders flocked to a speed store called "Super Shops", the brick and morter stores no longer exist, but now reside online, what im getting too, more than half the time, the customers that went there knew exactly what they were looking for, tried explaining it to the employees what they wanted, it was like pulling teeth, a real hastle, so the place got nicknamed, "Stupid Shops".
With the plethera of info online, be prepared to know more than the employees, its much faster to find what your lQQking for w/o the hastle of them looking at you like a deer in headlights, i know i dont bother asking for help anymore, i already KNOW what im looking for, if you cant find it localy, buy it online if possible.