Red Alert = 2% bonus possession penalty, Yellow triangle = 1%

Using one player there shouldn't be any problem, more often the benefit coming from the player OOP is higher than the penalty itself -Ive played almost all my seasons with 1 player out of position, ST as AMC with a 4-3-3 switching to 4-3-1-2, STs playing as AML/R... MCs as AMCs etc
Just try to don't have more than 1 player with alert if posible.