Target setting approach for internal operation of FI

I am setting GHG reduction targets for the internal operations of my organisation which is a central banking institution. The boundary only covers fuel emission of vehicles (Scope 1), electricity consumed in office and data centre (Scope 2) and business travel (the major emission in Scope 3). Our organisation is still expanding in terms of number of employees and office space (but not steadily).

I am considering to set our interim targets by Absolute Contraction Approach. However, since our office may be expanding in term of staff and space, can I assess the annual reduction in emission by intensity figures (e.g. emission per employee)? Can the same assessment method (i.e. intensity figures) applied to Scope 3 business travel as well? Or can the absolute targets be re-calculated every year when we have expansion?

If we have to pick other approaches for intensity assessment, which method (SDA/Physical Intensity) should be adopted?

Many thanks!