Hello,
PB advises to use native drivers. From PB 2017 help: "You can access Microsoft SQL Server 2008 R2, 2012, 2014 or 2016 databases using the SQL Native Client interface".
As far as your specific question on the 2 datatypes, MS SQL Server rather uses VARCHAR and NVARCHAR to store variable-length character data up to 2 GB.
At any rather, CLOB and BLOB (Oracle, DB2, IQ) datatypes are fully supported by PB 2017.
Appeon also supports them, but they can only be used in SELECTBLOB and UPDATEBLOB SQL statements.
Cheers,
Marco