H3D vs H3D II

I've recently found a really good deal on a h3d-39, after having recently sold my h3dii-22. I don't care that much about the difference in lcd, but I am slightly worried about the difference in IR filter coatings. Before I was not too worried, but I have heard some people say that exposures over 1/2 a sec are ruined with blown out flare in backlit or bright situations with the old h3d backs. This kind of worries me since I do alot of food photography with natural lighting that is heavily back lit, and is 2-6 seconds long in exposure. Anyone have any experience with this?