Answer A.) The back window doesn’t require much shrink. Just make sure you carefully examine the glass before you begin installation. Typically, these cars have silicon all over the place. It might be a good idea to cut just a tad short.
Answer B.) These cars have a reputation for accumulating dirt, so make sure to clean the edges thoroughly. You might want to try shrinking with 2 or 3 bubbles without much slack.
Answer C.) A detailed cleaning job is absolutely essential with the Chevrolet Chevelle. Personally, I clean it six times before installing. I only move on to the next stage when I can rub a paper towel across the glass without it becoming even the slightest bit dirty.