JOG, Eminent disaster, using the tensioner as a spring shock, was predicted by many , I have been waiting about 4 years and 16,000 miles for that to occur(I 'm not holding my breath at this time).

JOG , That's an idea that is a very difficult /if not impossible challenge. If the spring is to soft it goes hard ,if it is to strong it doesn't move ,either way it doesn't work .The fact that you need to work with two very different size springs, and trying to find a perfect working balance between them,  doesn't help matters. Even if you found springs with the nearly the same tension , they won't be for long as the chain stretches under normal wear ,or even if it doesn't, what have you gained? Nothing.
    I think the whole idea may be flawed. What I did may not be ideal,the spring may suffer over time (weaken) ,but if it does ,it should give some notice ( valve or chain noise).