There is an issue here also, that the reason a Grade 1 needs to have that ab-initio experience and 750 total TEACHING THE PART 61 MOS or equivalent, (most ICAO countries having very similar syllabi and standards) is because that grade qualifies you for a supervisory role, including HOO. Grade Threes need guidance and mentoring from a Grade 1. As do Grade 2s to a lesser extent.
f you have never flown the sequences in that type of aircraft, or been in "their shoes" in any other way, particularly dealing with the many and varied personality types and competency levels that you will be dealing with, then how can you effectively mentor/supervise someone else?
This is why he is a Grade 3 now and will have to be supervised by a Grade 1. If that rankles then civvie instructing is not for you.