I'm trying to edit and resave 32bit HDR's that are 32000x16000px. The only format options I'm seeing are Tiff, PSB and RAW. Are there any preferences that regulate this, or is it really impossible to edit and resave an HDR at this size?
Which file type are you starting with? HDR files are most likely going to be created from raw files. Just as a raw files can be edited over and over, an HDR file can be tone mapped to an LDR file an unlimited number of times, with as many variations as you like. When you are happy with the image you simply save as. Again it depends how you will be using it. For 3D applications you can use .exr or .tiff for example. To keep a master you can save as a Photoshop RAW.