then what would be the most effective way of using my spies in combat scenarios?

Is it possible to go war with somebody with a fairly limited army (plenty of turrets, some tanks and troops, no jets), so all attacks would be done with spies? Essentially, the traditional army would be for defense only and all acts of aggression would be done through covert operations.
How well would this work, and what would be a few good strategies to accomplish a win?

Make this happen. Push notifications would be awesome. I'd pay .99 in an instant.

Thanks for the advice, guys. I'm playing a tech strat (I know, not the easiest to start with), but I'm getting a feel for it pretty quiickly. I will join a clan shortly.

So, I've started off just building construction sites right off the bat. How many buildings per turn should I be creating? Any other tips for starting a new country?