Yes very true, it'd at least give a worn out baseline of trying to figure out what wire type was used / original spring rate and installed force was is all. (Music wire? Hard drawn?).
It'll be fine (and wise) to go about it the way that you are, regardless (this application seems like one where the more force the merrier). One thing that I'd look at is what the installed height of the spring is, that'll determine what spring rate you need to hit a force value at that given height. And also, what the max travel is. You can then base the free length of whatever spring you chose on that, and it may open up some additional options for aftermarket springs. (such as a longer spring at a lower rate... but installed gives the force needed to do the job). This is why "stretching" a worn out stock spring works, if the "worn out" rate is 10lbs per inch, and you stretch it an inch, you'll pick up 10lbf at the installed height. Kinda like going to Florida by way of Canada, but if it opens up "off the shelf" spring options, could be beneficial for people looking to do a direct swap.
Anyway, moral of the story, if I know what the "worn out" force is at the installed height, what the max solid height is (travel), I can add 10lbs to it and find an off the shelf spring through one of my suppliers that might work. Sorry for being long winded, just trying to explain where my dimented mind is coming from lol. :thinking:
