Just dont skimp on tyres mark. I've said it before and I'll say it again, I've towed all my life, My daily tow job is a work trailer with a gvm of around 1.8 tonne on a single axle. I need the maneuverablity that only a single can provide.
I spent 5 years working in a marine dealership where once again, towing was a multi daily occurrence. My own boats even up to 21 ft were slung on single axles. One of which I towed to darwin with a hr 30 skyline, (that raised some eyebrows), The ride home minus the boat and trailer with open speed limit was interesting.
Quality componentry and construction is the key. over kill axles, fish plates, ubolts, and most importantly a far heavier A frame than normal.
If you have limited room to maneuvre a trailer a single can sometimes be the only option, Its a cow of a job twisting up duals to get them in tight spots at times.
In saying all the above I am close to needing a trailer myself but given the poor weight distribution of a skyline I will probably lean toward a dual this time but i much prefer to tow and handle a single.