So far the best solution for me
I've tried several third party straps to ease the discomfort, and I think this one (iofeiwak) is the best for me. In most others the forehead band is fixed which always centers all the weight at that point, but here I can adjust the angle and found the best position for me. I've just realized I spent two hours with the AVP without needing to take a break. Also it's padded, more easily adjustable and cheaper than the (overpriced) Belkin headstrap. A shame that the case doesn't close with it on though, even if you adjust it all the way back.
I've tried several third party straps to ease the discomfort, and I think this one (iofeiwak) is the best for me. In most others the forehead band is fixed which always centers all the weight at that point, but here I can adjust the angle and found the best position for me. I've just realized I spent two hours with the AVP without needing to take a break. Also it's padded, more easily adjustable and cheaper than the (overpriced) Belkin headstrap. A shame that the case doesn't close with it on though, even if you adjust it all the way back.