I haven't used a long string in close to 20 years. I haven't broken more than one bow in tillering in the same time span. My bows don't take much set.
I cut the limbs close to final dimension on the band saw. Then I rasp them closer and start floor tillering. When I've got what I think is enough bend and the limbs feel equal, I string the bow to brace height and take a look at it.
Then, if the limbs don't look even, I unstring it and work on the strong limb or strong sections. Some scraping comes into play at this point. Then I string it up again and put it on the tree and pull it to whatever length shows stiff spots or comes to target weight or target draw weight. If adjustment is needed, I do that. I make 20 half or three quarters pulls and recheck the bend.
When the bow looks right, I go shoot it. This rarely takes half a day.
Making bows is only a means to an end to me. I don't want to be known as a bowyer or an artist. I just like shooting wooden bows and arrows. Some of your bows would look at home in an art gallery. As long as my bow has good cast and is stable in hand, I'm happy.