Garage Spring Stretching Tool?

(I'm the original poster.)
"Close the door part way, and shove sticks (wood shingle, bits of clapboard, or parts of a pallet) into the coils of the spring. Open the door all the way, and brace it. Move the springs. Un-brace-the door, lower it, and take the sticks out."
That was the best idea I found. I did that, using nails as the space holders, and it worked just fine. Adjustment made.
As an aside, all four springs already had the safety devices inside them, so this was not as risky as some feared.
Thanks to all, and especially Goedjn, for the suggestions.
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