Well, in a perfect world, maybe yes, maybe no, if its a bicycle only specific size and VAR didn't make it, then you may be SOL.
You may have to go with what you have or can find, I have several different multi thread files, 6 I think and still don't have the right pitch often and have to get as close as I can. Sometimes you have to blaze a trail and make the best of it.
At a certain point you have gather your chi and dive in, feel your way through and trust your judgement when it doesn't go wrong but try to be quick to recognize when it does and hopefully correct course before it goes too far south
The lockring above is a good example, if you can determine it works well enough to try it then do so with caution and diligence, keep an eye on it and see how it goes. In this case I would reinforce it well with loctite at least although I would go further, SG or even a tiny bit of JB.
If it holds together then all good, maybe only this one time but you have garnered judgement and experience that can mitigate some of this uncertainty next time.
There are usually only a few right ways, lots of wrong ways and a combination of those and more, my way.
I've made a pretty good living, won a heck of lot of races at the drag strip and solved many pita problems along the way.