How the heck do you get a 100% victory?

[caravel]

Very easily in fact. Just keep training spies from the start of the game. Yes you can do a few treason trials, and at the beginning of the campaign there are usually plenty of disloyal generals to bring under control, but there is a better method: Don't build the border forts.

Instead of constructing border forts in every province, build large numbers of spies. The spies both boost loyaly and kill any rival spies/assassins that pass through. Most importantly the spy will gain valour when he finds a rival spy. This way your spies effectively train themselves. If the border forts were there, the spies would not do the catching and thus would not gain the valour.

Once you've got this started it's simply a matter of moving them around to different areas. For example you may have a province where spies/assassins are getting caught every year. So move out your high valour spy from that province and move in a 0 or 1 valour for training. Conversely you may have a province where your 0 or 1 valour spy is not catching that enemy assassin that bumps off every emissary you train. In this case move one or more of your high valour (4 or above) spies (or assassins) into the province to get rid of this annoyance.

If you follow this system, by the time the bloat effect kicks in, you should be well covered, and you can then put up your border forts in the provinces that really need them and enjoy a very high level of protection and provincial loyalty in those provinces. I would advise that you simply don't border fort your whole territory however and avoid them completely if possible. Also if you lose the province and your spy is in there with the border fort gone over to the enemy - he's gone. If the border fort wasn't there, then he has the chance of starting a revolt in the province - hopefully bringing the province back to your faction.

Spies play a vital part in my campaigns, I simply wouldn't be without them.