I don't believe there were any significant changes between the 2011 and 2015 CBAs with respect to overage and substitution pay. I like the ALPA calendar flow chart, but there is really no substitute for going step by step through the applicable sections of the contract.
The first step is to determine if you are even eligible for SUB based on how you got the trip being dropped (Section 25.H.2.). If not, it is dropped without pay and you get overage, if you are eligible for overage (Section 4.BB.1.)
If you are eligible for SUB and/or Overage, you have a decision to make. But I really don't think there could be a "best option" because there are simply too many variables.
Instead, I think it is important to know exactly where to look in the contract to do your own calculations. Again, the ALPA calendar flow chart is helpful, because it tells you right where to look. Unfortunately, too many people don't. Sections 4.L. (Substitution), and 4.BB. (Overage Accrual and Compensation) are the two key sections for what you are describing. From there, you have to crunch the numbers and do the math to determine your best option. If you decide to accept SUB, you need to go to Section 25.H. and determine what your SUB windows are, and the consequences of accepting or rejecting a SUB assignment.
Finally, you have to make sure your pay reflects what you are due to be paid based on your decision. Again, it seems like a lot of guys don't take the time to do this. It doesn't take a lot of time to fill out a paylog. But you don't get paid for extra duty periods or disruptions if you don't. And sometimes, that pay amounts to more than what overage or sub pay nets you.
One thing I have to remind myself of when I encounter one of these situations, is I have time to make a decision. Time enough to open the contract and step through my specific variables. The "correct" answer depends on whether I need more time at home that month or more money in my paycheck the next month.