DON'T be concerned...
Been talked about a few times on these pages.
Leaving a "quality" coil spring "loaded" will NOT hurt them ! Even all the way to coil bind, you "might" loose a pound or two, but with a cycle or two, it will be RIGHT rack to where it belongs.
Not only has my mostly-expensive, coil spring (for testing my race engine valve springs) tester said this, and my work at work said this, and the WWII Browning Hi Power, magazine that I bought (MANY years ago), FULL of 9mm ammo, that still fed well, the spring designers also say so !
As fa as leaving a gun loaded over time (hours)...doesn't sound all that safe to me ! Doesn't take but a split second to cock a gun !!
Mike