In the described scenario I would most likely recommend using both the Sitecore Publishing Service as well as database replication to synchronize the two web datbases.
The Sitecore Publishing Service is an extremely fast option compared to the traditional publishing in Sitecore and it is not that hard to set up and run on Azure IaaS or PaaS if you feel adventurous.
However, instead of having to publish to two different web targets every time I would recommend looking into Azure geo-replication which is at least experimentally supported by Sitecore.
See https://kb.sitecore.net/articles/423602 for further details on database scaling support in Sitecore.