I understand GCP Private Service Connect (PSC) is an effective solution for enabling service-centric private network connectivity for GCP APIs and other hosted services within and across VPC projects/organizations/on-prem setup based on Producer/Consumer project model.
GCP documentation on Private Service Connect explains the purpose, PSC Endpoint and Publish Service configuration however I don't find relevant details on what should be an ideal location (or best practice) for creating and configuring PSC Endpoint, Publish Service when you have Shared VPC based network setup.
IMO, PSC Endpoint & Publish Service are network resources so the ideal place is to create in 'Host Project' of Shared VPC Network as a 'Host Project' is meant for centralized network management.
Also, having PSC Endpoint and Publish Service in 'Host Project' will help in sharing a single 'PSC endpoint' for all the 'Service Project' resources (which otherwise require multiple PSC endpoints per Service Project). However I would like to understand from you if you have come across and/or implemented such scenario.
Update: I tried a Shared VPC setup wherein PSC creation is allowed in Service-Project which means GCP doesn't restrict the creation of PSC in Service-Project.