Given:

Coolant Dots Overcharge %

  0           100
  2           150
  4           190
  6           220
  8           240

Curve-fit this data. The quadratic equation:

y = (-b sqrt(b² - 4a(c - x))) / 2a

fits perfectly when:

a = -1.25 b = 27.5 c = 100

Substituting in the values for a, b and c and simplifying a bit:

y = (sqrt(5*(100-x) 27.5^2)-27.5)/(-2.5)

Now, invert the eqn (non-trivial) so we can compute overcharge% from dots:

y = -(5*x^2-110*x-400)/4

Then compute overcharge% @ dots = (0,1,2,3,4,5,6,7,8):

Coolant Overcharge% Recommended%

0        100           100
1        126.25        126
2        150           149
3        171.25        171
4        190           189
5        206.25        206
6        220           219
7        231.25        231
8        240           239

(Recommended percentage always lower than thermal break-even, just to ensure the system is always cooling down, albeit very slowly in some cases.)

Conclusion: Don't bother running anything at 8 dots of coolant normally. The ~8% extra overcharge (only ~3.5% improvement over 7 dots) isn't worth it. If the difference between life and death is 3.5%, you should probably change your tactics.

Running 8 dots of coolant may still be worth it to quickly cool down an overheated system. But don't leave all 8 dots in the system once it's cool, you're wasting at least one dot of coolant that could be better used somewhere else.

P.S. If someone wants to put this on the Artemis wiki, go for it. I'm too lazy.

Useful links:

Curve fitting: http://zunzun.com/
Inverse function calculator: http://www.numberempire.com/inversefunctioncalculator.php