Well it is finished and the curves look great (to me) It only took me about 6 hours pin bashing
I may have a new record in the number of times I had to remove and realign every pin.
The bad news is that, as dozens of model railway builders have found before me, curved points are a pain. My Bachmann Royal Scot sweeps solidly and majestically round the flexi track curves at full speed before launching into the air at the points. The pannier tank just falls over on its side at slow speed.
My attempts to reshape the plastic frog to stop the wheels hitting it were a failure, and my attempt to curve the point blades has put the whole thing out of gauge. These goes ten quid.
I will try a Peco reaplcement and see if it is any better.
The reason why I was limited to second radius was that my board is only 1.0m wide, although if I ever rebuild it it will have be a 3rd radius width,