Tu 114,
You're post reveals you are well within this subject, which makes you a valuable "informer" in this thread.
1-Are you able to point out all airlines that are aplying the Dash 8 MFF (including the 400 and any other series)?
2- Are you also able to list all conditions (restrictions, limitations) that are aplied at Tyrollean regarding the operation of both series by the same pilots? Like: Minimum TT in one type, rest period between switching types, etc.
3- Although you consider this kind of operation feasible, wouldn't you find it safer if both aircraft were flown as two independent fleets? Especially in places where conditions can be harder than normal, i.e. short runways (eventually wet), strong crosswinds with associated turbulance...
Thanks for your help!