After soaking in acetone I soak in alcohol. If you have a lot of shrinkage it might be due to too much moisture being pulled out of the wood. Let it sit a few days and it should return to a more natural state by replacing the lost moisture in the wood from the high humidity in the air. I don't use urethane glues in any place that shows. As SKB notes it always shows. For repairs in hidden places it is fine. Acurglass works well in almost any repair.
The real issue to all repairs is prep work, good clamping and letting it fully cure. Do those things and almost any glue or adhesive will do the job. None like oil or even too much moisture. You can't over clamp it so all the glue is forced out.
One other overlooked thing is to figure out why the crack happened in the first place. Bad grain will not be fixed long term by any glue. (A knot is a knot). If a stock is poorly inlet glue won't make it suddenly stronger. Sometimes after the repair you will find a complete glass bedding is needed to make the stock right. Half effort repairs will rarely last and the first thing blamed will be the glue.
