First question to ask yourself regarding the correct weight of your suspension to match your needs is if are you going to add brakes to your trailer
No brakes will mean your camper trailer can legally be 750kg fully loaded so you will only require a light suspension to suit.
A good starting point if your trailer will have brakes is setting it up for around 1300kg loaded. That is the axle, bearings & suspension specs will carry the camper tent/awning, watertank, jerrys, gas bottle, sparewheel, kitchen unit plus all the other misc camping gear.
If you are going to add a boatrack, boat, outboard, extra fuel, extra water tank etc you need to reassess your trailers axle, bearings & suspension specs & perhaps step up to a 1500kg rated undercarriage.
An overview of how to match your trailers axle & bearings to your intended load to be carried can be found at
http://www.campertrailers.org/axles_bearings.htm
Both leaf & independent coil suspension can be bought off the shelf with specific load ratings. The tricky bit is matching the suspension to your intended loaded trailer. Getting it wrong can cause component failure at the most inopportune place & time.
If you intend to travel over dirt road potholes or endless corrugations consider putting shocks on your trailer. Shockies control the rebound of the leaf/coil so it does not bounce back at the same rate as it was depressed. The leafs with the little leafs on the reverse side are called rebound suspension & do the same job as a shockie.
It is a good idea if you are travelling into the remoter regions is to match the trailers wheels/hubs to that of your vehicle. You will then have two spares readily available around the 6 wheels. With the addition of a good tyre repair kit & onboard air system you will be able to get yourself back on the road in no time.
Rob