There is no difference between having one publication or multiple publications - there is no extra over head, no advantages for replicating static tables in one publications, volatile tables in a second.
However there are some advantages to splitting your publication into two or more publications.
The first is that with the independent agent option you can have multiple data streams going to your subscription database.
The second is that if you are deploying very large tables you might want to break these into seperate publication so
1) you get the parrallel streams of data sent to the subscriber when you are building your snapshot
2) if your snapshot deployment fails and you have lets say 6 large tables in a single publication, you wil have to resnapshot and resend all 6 large tables. By breaking this up and one of the large tables fail, you will only have to send this large table again.
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