Redheart,
Sorry if I confused you.
What I meant is "springing" the barrel by feel, rather than clamping down, where you cannot feel what is going on.
No way is best, just whatever you feel good about or confident in.
Springing a barrel just means putting it between two fairly solid surfaces, (like the apple tree fork) and pulling on it quickly and letting it go back. As soon as it moves a bit you will know it, as you will feel less return pressure.
In practice, you pull on the barrel, and feel it return, and keep pulling a little harder until you feel a slight give, then look along it and see how much it has moved.
(or use a straight edge, having used it as well prior to springing it.)
Hope this helps!
Richard.