In MTTs, you can make certain range assumptions to figure out if a play is +ev and by how many BB it is +ev.. Something ive been thinking more and more about is: How +ev in terms of BB relative to stack size must a play be for it to be worth making and how to form guidelines based on your theoretical roi (the roi being from point where hand in question exists until completion of tournament).

For example... A specific play may make .09 bbs when 30bbb eff and may not be worth taking because your overall edge is too large however... if 4bb Eff a play that is +.09bb would seem more enticing. 

Do any RIO pros have any insight regarding parameters/requirements a play must make in BBs relative to stack size for it to be worth taking (with something close to your theoretical ROI considered)?