...Na6 ...Nc7 manoeuvre

Well usually Na6 is not how you would choose to develop the knight (knights on the rim are dim). So if you have to do it you are going to need to re-route it to a better square. Options -

Nb8 would seem pretty pointless and time-wasting.

Nb4 possibly good if allowed and you can hit a Qc2 and a Bc4 for example, then exchange Knight for bishop. But if you don't have this option the knight will probably be loose on b4 and will be kicked backwards by a3. 

Nc5 probably in your dreams because the square will be covered by a pawn on d4. 

Nc7 maybe the best option as it will be secure here and controls some important squares e6 and d5, adding influence and control in the centre. 

But of course, it all depends on the specific position.