[Purna]

So, let me see if I understand this...

If you have 5 roughly equal sized trading partners, and they have been your partners for 20 turns or more, then 50% of your mineral resources come from your own empire and 50% from trade.

Until your trade reaches this level, you will gain more from a point in mining aptitude than from a point in political savvy, right? (Assuming that is, that you are not constrained by organics or radioactives. Political savvy is a three-for-one deal, where two generally don't matter.)

That is, mining aptitude is a preferable expenditure until you go over the 120 threshold, at which point political savvy starts to look more appealing.