I am an Digital Marketing Consultant. Making creative digital strategists to produce innovative and unique, data-driven campaigns about industry trends.
Best way is to create product feed with the 8 products with Google shopping feed specification. Link it with merchant center and start the shopping ads.
I suggest to add more products if you want better results. 8 products does not give you much traction.
You can set the process for running Facebook campaigns for many clients.
There are few tools available which can be helpful to auto schedule your campaigns.
I recommend to use sub directory if you want to take the SEO advantage.
In sub domain, authority & link juice will not pass and Google treat every sub domain as a separate entity.
I hope this helps.