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To me it would depend on how comfortable I felt instructing in a twin with the minimum PIC required. If you are current and quite familiar with the twin and IFR procedures and flying/instructing single engine approaches, why not? Might be a little expensive, but what in aviation isn't?
If you have the knowledge and instructing ablilty, go for it!
Good Luck!
One other thing;
How much of your time in the twin has been spent towards your MEI, what I mean is that as I did my mutli checkout I did it all from the right seat and doing drag-demos, Vmc demos and so on. Getting to know your plane really well would be key to passing a MEI-CFII ride.