Do yourself a favor and have someone build you a set of springs that are at least a nine leaf pack...maybe even up to eleven. You get really thin leafs but gain a lot of height in the thickness of the pack. This gives you a flatter arch which rides better and usually will hold more weight.
I had Deaver build mine. They were kind of expensive, I think I paid just over $700 for them but it was well worth the money. I've had them on for two years now and they ride great, no sign of sag and carry the weight of two kids, a big dog, ARB fridge and a ton of tools, along with the tongue weight of my trailer.