Best Practice: what is the best practice constructing services

[haniyasin]

Most Data is relational in nature , what is the best practice to deal with this situation for example:
1- if i have a product table/collection and another related product details table/collection should i :

a- construct services for each table/collection and deal with relations, and joins inside the application using hooks
if this is fine how can i construct a service without exposing it to sockets/REST (i.e internal service)
b- construct a custom service for grouped/related tables/collection

2- what is a good limit for the number of services i can construct in a single monolith app (from your real world experience) knowing that at least 1000 or more concurrent users ( i know i can use feathers-sync to distribute load) but the question is is it fine to have a feathers app with say 900 services , or feathers is more oriented to light weight apps
i appreciate your guidance

Microservices is fine to divide an app but it introduces another headache of Orchestration