I would suggest a complete IR (no longer referred to as CIR) for the training. When you conduct the initial assessment, have the examiner include the PIR and all associated endorsements at the same time.
This provides you with the ability to continue an IR flight if your IR recency lapses, as you can plan a Private IFR flight.
However as others have pointed out, currency is the key. Even if a PIR pilot is legal, but hasn't flown in 5 months, is it safe?