I imagine I'm anybody but the first person to discover this technique, but I figured I'd pass it on to anybody who might be able to use it.
If you deal with heads (or blocks for the flathead crowd) that have short side turns that are really sharp, you probably already know how tough it can be to get a nice radiused shape to them. Oh it can feel pretty good, but after you mold it you find it's too tight or laid back too far and too tight by the seat, just wrong, or whatever...
Here is a way you can check the profile as you go. Cut a short length (maybe 3-4 inches long) of regular old plumbing solder (I used different diameters, but new 1/8" works pretty good) and lay it against the short side turn, pull it tight and take it out of the port. You can lay it against a white background, a template, a sketch or anything else your heart desires and clearly see the exact contour you've made.
I've found this super helpful when the going gets tough, it's the end of the day and you're hands are insensitive and you can't tell a golf ball sized radius from a pea...It helps you find ridges (or more specifically where they are located) and defines the general shape very well. Also good near pushrod junctions etc.
Sean