Question: First of all I just started doing barre chords after learning ordinary non-barre chords. Problem is they don't sound so well, so my question is, will training with hand grippers help me achieve this? Because I've been applying equal pressure and they still sound a bit off, only a bit off.

Answer: 
It turns out that strength is not what is needed to improve your ability to finger barre chords, or any chords. It's mostly about precise placement and using the minimum amount of force to hold it down.

It's not necessarily that equal pressure is correct. You just need the right amount of pressure for each fret and string.
guitars are all about practice, practice and practice. so yeah if you are performing for someone use them, if you are practicing then don't because today you might not be able to do it but even if you try 15 minutes a day( not at a go) try to hold the chord, check if each string is ringing, if not readjust your position(chances are that it is still not ringing), still you practice shifting and strumming, keep on doing it without losing hope and magically one fine day you will get up and notice that you have done it. it might take anywhere between a week to two months. I couldn't press the b string whenever I had the shape of e major for 3 months! so its just a matter of time. for some its less, for some its more. playing guitar has nothing to do with talent. but what comes after playing is. you can play each song you listen for the first time in first go but you may never be able to compose some( I know that cause I don't have the musician in me ) but nothing should ever stop you. if you believe you can, you will end up doing it some day and that might just not be today. Good Luck!