Help on specific plays

I'm quite new to the game of blackjack and just getting some counted games under my belt. I use KO.
So my question is about hard 16 vs 10, hard 2 vs 14 and maybe hard 13 vs 2 (in 6 and 8 deck games).
Is 16 vs 10 so clear cut as to always hit according to basic and always standing on high counts?
When do I hit 12 vs dealer 4, if ever?
and is there any index for hitting 13 vs dealer 2?