Having to import products from a PIM solution and seeking recommendation on the best way to handle attribute_set. Would this typically be mastered in PIM and extracted or is there any other suggestions?
By attribute_set, I guess you might be referring to Family in PIM. On Akeneo PIM software, you can easily create families which consist of an attribute set and create a product belonging to a particular family.
You can even assign the product to one or multiple categories in PIM and once you are done with the product information, you can export it to your Magento Store using Magento Akeneo Connector
It depends on the PIM solution. In Bluestone PIM, the Mangento integration pulls all attributes from Bluestone PIM into one attribute set in Magento (called 'Bluestone PIM Attribute Set'). This makes it easy and well-organised for grouping all attributes from Bluestone PIM into just one attribute set.
Please note that this will not work if a user has multiple attribute groups (separate groups used for different purposes such as Marketing information, Logistics information, Care information etc), and wants them to be synced in to the different groups in Magento.