Hymns, like buses and some brothers, are normally better separated than together. They all need healthy gaps in between. But that general rule enjoys the odd exception.
Some churches run hymn marathons, where all the hymns in a new book, or the top 100 after congregational voting, are sung through non-stop, often with teams of organists and choirs. Usually there is money involved, and through sponsorship the singers convince themselves they have somehow created cash out of nothing. All this has educational value of a sort, but whether it is worth the price of trivialising the hymns must be open to doubt. It does not seem quite what Monsell or Montgomery had in mind.
But there are other ways of doing your Songs of Praise or Sunday Half-Hour. America is way ahead of us in this, but hymn festivals are not unknown over here. The hymns are not stacked up end to end, but interspersed with Scripture, prayer, biography or meditation. At least three ways of doing it are well-tried.