How do + and - signs relate to percentages and sliders? How to allocate sliders?

[Emergent]

I've read numerous guides showing exactly what's +++ and what's --, and some that recommend certain percentages, but I have yet to find a definite guide on exactly what the +/- means in terms of percentage.

For each of "+++", "++", "+", "-", "--", and "---":
- Where should the sliders be? Does +++ mean "slider to the maximum" and --- means "slider to the minimum"? So does + mean "slider to 60%"?
AND/OR
- What should the percentage allocation down below be? Does --- mean that it should be 10% of the bar down below? Does ++ mean 40% of the bar down below?

And finally... how do you perfect exactly how much to allocate each slider? Sometimes I wonder whether I got a 9.5 instead of a 10 because I was off by a few pixels when dragging the slider with my mouse.

Do people use physical rulers on their TV to figure out exactly the right place where to put the slider? Like, measuring out the whole slider =10cm on the TV, so put it 6cm from the bottom so that you get 60% allocation because it's "+"?

I feel like I should almost use a ruler and sticky note/markings to figure out and mark on the TV where the sliders should go depending on the +/-. Kind of like you'd manually put a small sticky note crosshair on the TV in the right place for a first person shooter that doesn't give you a crosshair.

I can ask the same question about percentages down below. It almost feels like there should be an "auto-allocate" button once you have the cumulative hints telling you exactly what the allocation should be (i.e. with no question marks).

If anyone can shed light on my confusion over this, I'd be exceedingly grateful.

[Mr. Rain]

+++ means crucial detail for that part of the game.
++(-) means it's necessary but not primary.
--- means least necessary.

Best thing to do is give the most dev time to the +++, then 2nd most dev time to ++(-), then the least possible dev time for --- which I believe is around 20%. Just enough for a feature or two to be included.

The best info you can get are from your features. If they start to show a percent ( 99% - 98% or lower), then you'd need more time for those features. So, using that, you can find the lowest possible tolerance while still having the most amount of features included by lowering the bar until the percentages begin to appear on the enabled features. Then slowly raise the bar until it's back to 100%.

There's also a percentager mod to help with that.