That was a good post. I don't make a lot of elbs but sometimes I do struggle with the shape I want. Last week I made 5 bows to end up with one how I like. One of them took set mid limb, another took set in the handle, another came out light and another had too much mass for my liking.
If you are blessed with a good eye for tiller you can get away with a little more than those of us who lack the artist eye. I find it is important for me to not only look at the tiller shape but also manage my tapers on the limbs not matter what I think the shape looks like.
I start off pulling to full draw weight right from the first pull. If the handle area bends too much I know right off the bat I started too thin. So I would say manage your tapers carefully throughout the process as well as keeping an eye on the tiller shape to keep it in ballance.
As for long string, last week I started off with a string that hungdown 12" with a little tension on it. I got it to 50#@23" with this string, I changed to a shorter string and it read the same thing, I finaly braced it and I was still getting 50#@23". So don't let the long string fool you by thinking you are still far away from your goal because of a loose string.