LE,
It would not be a matter of experienced in RHS operations only, but a suitably experience pilot be trained to fly from the RHS. An instructor without appropriate 'High Performance' ME a/c, actual IF and Night and commercial experience may not be suitable; hence, 'suitably experienced'.
Operators of >5700kg aircraft already have these matters addressed in Part C of their company ops manuals, in sections relating to training of training captains and training of check captains, so these could be a good source to model from. The training for supervisory captains may not need to be as stringent, but a formalised approach to holding the company qualification should be a requirement before supervising of ICUS pilots, considering that the flights may be in all sorts of bad weather and dark night (or combinations thereof).
Imagine, if you will, a supervisory pilot trying to recover a plane, possibly out of control, or in an unusual attitude, in IMC from the RHS. That is a real risk that exists in flying with inexperienced pilots under those conditions in high performance aeroplanes. That's not an easy ask, even for qualified people.
A formalised syllabus and standard of competency should be enshrined in the company ops manual and approved by CASA. Portions of an instructor rating syllabus could be used for training pilots to fly from RHS and deal with the physical and optical differences of doing so, and other matters that the company deems a requirement for a supervisory captain, and approved by CASA. The candidate could then be certified as competent to act in command from the RHS and be approved as such by the Chief Pilot.
Prior to approval as a Supervisory Captain, the candidate should have to demonstrate a level of knowledge in matters such as, but not limited to, IFR procedures, General Knowledge, aircraft type technical and operational items (including normal and abnormal procedures), and also demonstrate a competency in the prompt recognition of errors, the ability to clearly advise any corrective action and take control at a point not too early, but before the situation becomes critical etc etc.
A realistic minimum of actual ME command experience could be say, 1000hrs TT, 500ME command, with 150 hrs command on type and at least 50hrs IF, and if night operations are included, 150hrs night. Then again, these are probably not high enough, in real terms.
With regard to getting the qualification, my suggestion would be to go to a Flight Instructor rated training organisation and get some lessons in flying RHS, maybe they can give some sort of letter of confirmation that this training has been undertaken to a satisfactory standard.
I am not sure how much of these matters the proposed changes to Flight Crew Licencing addresses, cause have not perused the NPRM sufficiently, but any correction or opinions welcome.