BB....Best thing I ever did in learning the different and many calls that hens make is to by a set of cassete tapes. Real turkeys 1,2,3,&4 by Lovell Williams will let to listen too every call that a hen produces Spring thru Fall. Sit down with these tapes, take your call of choice, then listen to each call and try to replicate it. Also works great on the way to work with a diaprahm call stock in your kisser. Great way to practice and NOW is the time!
Personally, I like slate calls overall. The old Quaker boy double slate I have has a quality tone that I(and the turkeys) like .The key to it is the solid plexi-glass stricker that provides a deeper tone. Glass calls dont always work well when they're wet either! The cheap plastic strickers emit a higher pitch tone, but again any and all will work on any given day. Depends as many have said on the mood of the bird & what sets him off that day!
Push-pin type calls are simple to use and can be attatched to the gun. Box calls are harder to learn but there sound will carry farther on windy days. Having a few differnt calls CAN be the difference between success and failure. You dont have to be a master caller to call in a gobbler but knowing the calls and being able to duplicate them with different type callers will surely increase your odds........TF