As you slide down the banister of life, may the splinters never point in the wrong direction!
When implementing an OctopOSS, consider building a single, transparent team where the customer’s resources blend with the vendor’s. The vendor knows the minutae of their product (they should!), whilst the customer knows the intimate details of their company far better than an outsider could. Both sides of this fence must be straddled by the project team. Try to do it without getting splinters.