So if I understand correctly, the period of time during which I add solution B (silver nitrate) into the solution A needs to be shortened, right? The book 'silver gelatin' mentions it should take time of about ten minutes, but I will try to shorten it.

Regarding the Bovine gelatin: I live in the UK and I can't find any company that sells this particular product. However, I found that SILVERPRINT sells photo quality gelatin so I will order it from there.

Thank you very much to all of you guys for your amazing help. I really appreciate it!
I will post any results one it is done.