Eat carbs before gym, no worries about being so specific on PWO carbs. You will already have fuel in the body for it to take advantage of.
Regardless, if you are fueling your body already, then the impact of PWO has a very diminished result. Focus more on getting your macros and leave the little things, like what specifically to eat PWO, and your results will speak for themselves.
That said, just stick to your macros, and things like pop tarts, cereal, ice cream, fruit etc should all be just fine. Now, if you were using slin, then I would have a more strong opinion about specificity.
As usual, JMO.