Alistair -
I agree with all of that except the part about transitions on a typical layout being too long to be practicable. If you set out the transitions as explained in the Scalefour Digest, then a transition from tangent to 30 inch radius with a shift of 1 inch is just under 20 inches long. I have used these in the past with great success, including back-to-back half-transitions between reverse curves.
Apologies for misspelling your name first time!