grip training / CoC gripper

My grip strength improvment are always been slow but gradual. Now it is holding me back on deadlifts and other shrugs. My current lifts (raw, no belt) are
Squat 330 lbs
Bench 275 lbs
Deadlift 400 lbs

I can only pull 330 lbs without straps though, which is not good.
I plan to buy some captain crush grippers. What grade should I start with? I am thinking about starting on gripper no. 1 (140lbs) and do negatives on No.2 (190 lbs). Is that load alright? or should I start on the trainer gripper, which is 100 lbs.
Also is it possible for me to gain enough grip strength and endurance to do 3x10 shrugs with 440 pounds without straps?

Well if it helps,

I'm close to closing the #2,
#1 is pretty easy, and sold my T cos it was too easy

I can DL 475
I can pull 575 off the rack for a 5 sec hold. (like doing static holds for grip)

the grippers are good you may wanna start with the 1 don't even bother with the trainer.

you don't wanna focus ALL your grip work on just the trainers though. I brought up a problem about grip myself on one of these threads check it out.

if you can pull 330 without straps I would say skip the trainer. When I first got my No.1 I could pull exactly the same without straps. I couldn't close the No.1 with either hand when I first tried but after about a month of working on it it was really easy with both hands, the trainer would have been a waste. The no.2 is a beast though.

Do you do any holds? Load up a bar with some serious weight, set the pins a little above the knees, grab the bar, stand up and see how long you can hold the weight. You can set the bar up higher if you like, you're not working the back just the grip. Try doing those at the end of your workout though. As my grip starts to go I really start to squeeze the hell out of the bar. A good trick anytime the grip starts to go when doing any exercise, IMO.

It's good that you have an idea where your problem might be, now all you need to do it work on it. :)

Jugg