CDS Views w. Parameters / SQL MACROS

Need a clarification on SAP Note 2801989,

Is there any way to measure the performance before and after enabling the SQL Macros.

Once CDS Views are converted to Oracle SQL macros (Step 3 of SAP Note) can we disable the SQL Macros (with entry CATEGORY = 'NOSQLMACRO')

and can we revert back SQL macros to CDS Views, if we don't want to use it.

Our Client is asking for these clarification before we implement the SAP Note 2801989