Minimising downtime implementing merge replication on live system
The biggest time saving option is to generate the snapshot and compress it with your favorite program, like 7-Zip, copy the compressed snapshot to the subscriber using file-copy or FTP, and then apply it locally using the -AltSnapshotFolder Merge Agent parameter.  The existing Product database can be left in place while the snapshot is being copied over and client applications can operate normally.

The way this works is open the SQL Agent job for the Subscriber you wish to deploy the snapshot to and get the Run Agent. command.  It looks something like this:

-Publisher [PACIFIC] -PublisherDB [TestDB2] -Publication [TestMergePub1] -Subscriber [PACIFIC] -SubscriberDB [TestSubDB2] -Distributor [PACIFIC] -DistributorSecurityMode 1

Then, grab the snapshot files from the publisher and compress it.  For example, on my server I compress the snapshot folder found in C:\Program Files\Microsoft SQL Server\MSSQL10_50.MSSQLSERVER\MSSQL\repldata\unc.  I then copy the snapshot folder to the subscriber using file-copy or FTP and decompress it in a folder called C:\TEMP\unc.

So looking at this on the Subscriber I would see this for the snapshot folder:

C:\TEMP\unc\PACIFIC_TESTDB2_TESTMERGEPUB1\20130207200123

Then from the command line on the Subscriber, run this:

c:\Program Files\Microsoft sql server\100\com\replmerg.exe -Publisher [PACIFIC] -PublisherDB [TestDB2] -Publication [TestMergePub1] -Subscriber [PACIFIC] -SubscriberDB [TestSubDB2] -Distributor [PACIFIC] -DistributorSecurityMode 1 -AltSnapshotFolder C:\TEMP

This will apply the snapshot locally and will be significantly faster then applying it over the wire.  Downtime at the Subscriber will be minimal.