I've been pouring that mold with 4/0 hooks in the 3/8 cavity and have not had much problems since the first time I poured it. I think any new mold has a learning curve and can agree with what Brennan has said.
I do get molds very hot, using a hot plate to pre-heat and have also been using a Hot Pot electric ladle to pour. I have not tried pouring it with my bottom pour.
I don't bother with heating hooks, they get hot enough if the mold is plenty hot. They don't have enough mass to affect the mold or lead temp if the mold is plenty hot. Using a hook that positions centered in the cavity to me is more important, and I've used all 3 hooks in that mold, Victory, VMC & Mustad.
Laying out your hooks and being capable of getting them in the mold quickly helps with keeping the mold hot. I use a good surgical type tweezers with some hooks & other hardware, and a piece of wood dowel that's been sharpened on the one end in a pencil sharpener. I've used metal tools too in the past, but they tend to get magnetized and then the hooks want to stick to them. Wood dowel is fairly inexpensive to replace too.
I also have been using primarily recycled wheel weight lead. I have several hundred pounds of it and seldom use soft lead for any pouring. Making sure that you're using clean lead ingots and not scrap straight into your melting pot also helps and I skim it off frequently so the oxidized lead doesn't pour into the cavity & block it up. The only other lead I'll add to a pot is sprues that I had previously removed from what I've poured.
If you only have a bottom pour, keep it closer to full, as that mass of hot lead will help in maintaining a fairly consistent temp once it is all molten.