IMHO it doesn't really matter how many hours you have accrued as a multi pilot if they have all been operated with both the engines/props operating normally.
Yes, multi instruction is a very risky business but the emphasis has to be on the potential MEI meeting the standard on a specifically designed test of their skills.
FWIW in the USA their is no hour requirement to become a flight instructor although you must have 15 hours in cat and class (and to teach in a twin you must have 5 hours on make & model)