+1 This is really probably the most important part. Vary the revs, don do a lot of highway driving at steady speed and don’t let the engine idle for a long periods of time.
With synthetic the engine will bed is as fast as with mineral, the reason is somewhere else. There is one big difference between mineral and synthetic. If you overheat synthetic oil, it deteriorates. If you overheat mineral, when it cools down it gets back its original properties. During the run in period there are components in the engine that are not yet smoothened by their movement, or are not seated properly, or the imperfections on their surfaces rub. On these surfaces the micro volumes of oil can really overheat to hundreds degrees. In case you have synthetic, this means that it will deteriorate faster.
However, the manufacturing tolerances and surface finishing is much better now and the parts are much more precise and don’t need to bed in as much as 30 years ago. The bedding in process doesn’t have so big effect as in the past and you can use synthetic from the start. However, for the peace of mind, I would recommend to change it sooner.
At the moment I am going to run in the rebuilt engine in my GTA. When the snow melts, I plant to do a lot of countryside driving over the weekends and to change the oil after 2000kms.