Trying to find what kind of weights or how to get a more defined and larger back.

Anyone with some tips ?

At the mo I'm just using (forgive the lack of technical terms) some metal handles with weights at either end (one handle per hand).
It's loaded with all the weights I got with it (6.8kg on each hand)
So any lifts I could do with them to increase the back is a good thing

 

Lat pull down
Lat raises
Seated rows
Standng rows
Bent over rows
Chins(wide grip)
Deadlifts(lower)

I could carry on....

You wont work the back very well at home with just a set of dumbells.

You idealy need a lat pull down machine

 

yeah as Joe30 says you will do well with a lat pulldown machine if used correctly will get you big gains! also if you go to a gym that has a lower back stand this to is good to tone and strengthen your back!

 

I love doing back work.. Lat pullldowns all day long

Lower back stand is good with a bit of weight in your hands