AAH, yes, it's all about 2018 Christmas Layout memories Jeff
Thought I'd post an image of the VERY expensive custom tools that I use. No software for me, just these VERY expensive tools:
My 'Grid' is based on 1" = 2'. So I found washers and other round objects that match exactly to 27", 42", 54", and 72" curves based on that ratio. The cardboard piece on the left is for 45 degree angles coming out of curves , such as after one 27" or two 54" curves, while the one on the right is for use with 42" curves allowing for coming out after one curve or 2 (30 degrees on one angle, 60 on the other).
Like I said, VERY expensive stuff
- walt