PE: if you mean fogged sample of a real paper then yes, it turns black within 3 seconds. If you mean the paper I coated then it took about 60 seconds to get to the state as in the photo. Btw, I am using Ilford Multigrade 1:9.

Hexavalent: I checked the details of the gelatine and it is 'porcine', intended for confectionery and jellies. I wouldn't think that could matter as long as the bloom number is high.