This could be totally anecdotal, as I have only had boob eggs for the first time this year. I have had two different clutches and a total of three boob eggs. One in the first and two in the second. In all three instances, they were the last to pip. One of them pipped fully 6 days after the rest of the clutch, and to be truthful, I cut it which I normally do not do. For my future instances, if I should have a boob egg, I will wait at least a week or more after the rest have pipped before I intervene. My expectation prior to this season would have been that they would pip early or at least on time, given there is less mass to build into a snake. However, my revised thinking is that with less mass, there is less of a vein structure. Thus, in the early stages of the development process, they are slower out of the hole and take longer to catch up.
With that said, I was wondering what are others experiences with boob eggs? This could be helpful to collect some data for future hobbyists to manage expectations.