Re: Bloodstone + Dark Tower
I think with the ideas you have going on you shouldn't worry too much about the steps just consider the consequences for future changes.
For example, the steam engine brought incredible changes with it. The entire industrial age is due to that one single invention. So if you are going to introduce something as world altering as that, you need to be prepared for what not only the players will do with it, but also what the rest of the world will eventually do. That was the reason behind my original comments about gunpowder. It literally changed not only the face of the battlefield, but also gave rise to incredible new discovers that were needed to be able to handle the explosive force of it.
If you look at history, you'll see a common trend to technology and "ages". They are almost always centered around periods of great war, or tremendous technological breakthroughs, which more often than not occur during war or right after.