John Cutler
Neil, before you get too carried away, please test your new trackwork with an 0-6-0 loco. My first couple of C&L turnouts were fine with short-wheelbase wagons, but misbehaved with anything bigger!
If you are successfully using steel, I am not sure you should convert to nickel-silver rail. I believe (but could be wrong) that the co-efficient of expansion of steel is less than nickel-silver. So tightening up of trackwork and large expansion gaps should be less of an issue with steel. Iain Rice recommends steel and suggests that traction is better steel to steel.
Personally I avoid steel despite its better appearance. I find it difficult to cut/file/solder and invariably rust appears. The biggest issue is that pick-up from steel rails to steel tyres (Alan Gibson or Markits) is less efficient than from nickel-silver to steel. Ultrascale nickel-silver tyres are an answer but one that is expensive with long order lead-times and a limited range of wheels. Long-term (but hopefully soon) the answer to this is battery power.
One thing I would love to see is rust-coloured nickel-silver rail with a polished top. Just think of how much fiddly painting this would avoid. Coloured steel is a possibility but I do not think its surface is conductive.
I too have an issue with tightening up, and also with expansion gap widening (OK my track is awful!). Rather than pursue it here, I have started a new topic in the Track section of the forum.