Yes, I'd be interested in hearing how it goes. But I'm not sure how you can 'measure' any savings w/o going a year or 2 w/it (through 4 seasons, or so.) In addition, the paint is 'touted' to save about 2-3% (per my readings.) That would weigh heavily on paint vs. foil vs. chips vs. r-board. IF you have the soffit vents, in addition to AT LEAST gable vents, perferably ridge vents, then I'd consider a product that would 'do more' for you in terms of savings.
Those are my final thoughts, for the moment. WHen you eventually post back with 'how it works out', be sure to 'cite' the original problem, a few odds and ends, and the cost of the install/material and any savings you've realized. For now, my best to ya.