Ordering all grippers will cost a lot of money, But they all have a use. a lighter gripper can be used for strap holds and overcrushs.
i still use my T from time to time.....and i am going for my 3 (i have closed T,1 and 2) I have cut it down so there is more range of motion (once you convert to a normal gripper to a cut gripper.....it feels like you are stopping short...it develops your close)
other higher grippers can be used for a negative crush or straight up negatives.
Legion Kreinak2: some people have trouble with the T (even though training with weights) and CCJ and myself live in australia. The postage can be quite high....so the less times ordering the better. having the chance over i would have ordered T,!,2,3,4 all at once.
Iron lion is on the money. There is little cross over. Specificity is the key to grip training. The more you learn the more you will understand the different functions of the hand and wrists.
The Red Dragon: that is untrue. there are many who have closed the 3 with tiny wrists and forearms. I have a video of a man closing a number 3.......10 times! he looks like an average dude of the street.
also only 1 person has closed a number 4...but over 100 have closed the 3.
i believe any MAN could close a number 3 with the right dedication and training
check out heath sexton mashing the number 3 many times
http://www.cyberpump.com/albums/GripBoardGallery/aad.wmv
do you know how hard that is? (dont give me the "he didnt open it the whole way bullshit)
how big are his forearms? not very