There is an old adage that a bow full drawn is 7/8ths broken.  We've had enough arguement on that over the years to fill a series of books, the the spirit of the adage says a lot.  The longer it is at draw the thinner that 1/8th gets.  ADB isn't steering you wrong!
The roll of masking tape is yet another variation on a long theme.  Didja know that the bottom of a bottle or can does the same?  However, I have found that too many checks of the tiller while tilting a bottle or can, often ruins the tiller.   

  Not sure what it is in the process that causes things to go wonky, maybe I need to do more research.  
Never the less, any trick that helps you turn out a workable bow or improves your technique is something worth sharing.