Terry, you weigh exactly the same as me and it also took me a while to find the right spring ie 26kg.
I have the nitros though and to be honest I haven't heard many talk highly of the cheaper units. All I can say is the nitros are brilliant now and with the progressive fronts as well I have just forgotten about most poor road condition. To a point that is cos some roads are just a disgrace and can test anyone's patience.
BTW, with mine I have found the best pre-load adjustment to be about 5 or 6 turns down, thereby leaving me about another 25 to play with.
