Well said Octavius. If I may add my two cents...
I would also add a little more in general on the Regulative Principle. Some misunderstand this and hence reduce it to an absurdity. The RP regards the required elements of worship. That is, these elements are the only elements allowed. The Confession lists many of these required elements such as the reading, hearing, and preaching of the Word, prayers, singing of psalms, and the sacraments. But the RP also allows for the means which help to carry out these required elements. For instance, we are not told anywhere in Scripture to worship in a church building. Does that mean we aren't suppose too? No. It's a circumstantial means to carry out our required worship. It's much more condusive to worship in a church building than during a snow storm in an open field. It is the same with using a liturgy/bulletin to organize the worship service so that the required elements are fulfilled decently and in good order. We put the songs in music books to make them easier to sing. We encourage everyone to read and use their Bibles in English because that is conducive to those required elements of reading, hearing, and the preaching of the Word and our participation in them with understanding. We pray in English so that the congregation can fulfill that requirment of prayer, and do so with understanding.
Finally, the issue is not which view of the RP is too extremely conservative or liberal by today's standard, but which view is biblical. Just because many in even reformed churches today have departed from the Westminster view of the RP does not mean they are right to do so.