Could you post the complete error message you get regarding the conversion failure?  Also, what is the date format on your system, is it mm/dd/yyyy or dd/mm/yyyy?

A better way is to copy out what you want to keep, truncate or drop the original table, copy back in or rename the table to the original name;

If you are looking for the algorithm, not sure I can help.  You are aware that hashbytes function in SQL Server implements SHA algorithms, you just can't see the code.

I think it may come down to the collation of the database where these tests are being run.

The idea, really, is that you should control the growth of the database instead of letting it grow whenever it needs to grow.  And I would stay away from %...

Only time I get to...

Try this, uncomment the EXEC statement.

DECLARE @SQLTemplate NVARCHAR(MAX)
        , @SQLCmd NVARCHAR(MAX)
        , @SQLParm NVARCHAR(MAX) = N'@iViewDef NVARCHAR(MAX)'
        , @ViewName NVARCHAR(256)
        ,...