hat I want is to purposefully overexpose to create halation around the object, as you can see in the photos I've posted.
I doubt this is a good way to get halation. Sure, there will be more halation as you overexpose, but it will be in line with the increase in image density you get from the overexposure, so if you print or post process the image to have normal brightness, you'll tune the halation down with the rest of the image. Maybe this relationship breaks apart in your favour at extreme overexposure, but I think you'll have problems with image detail in the highlights then. Unless you want blown out highlights like in the first PIC in post # 36. BTW the hat in that picture is much brighter than the bright hair in the second one, as evidenced by the halation -ha-, so subject matter and lighting play a important role if you want that.
Again, film that halates more is probably your answer. Another possibility to get a similar effect are lenses that produce "glow". I think this can be a consequence of haze, but also of undercorrected aberrations of some sort, so probably older lenses are a good bet.
You'll get a more drastic effect of that sort with pantyhose over the lens or a variety of filters labeled "mist" or something of the sort. The better, more subtle ones are from the cine world, there was a thread here about that a while ago.
Your style model might have used any of these things, most likely the lens choice, and if we're sure he used FP4, maybe it was an older iteration of it had worse antihalation properties than the current production.