https://www.amazon.com/gp/product/B09M9XKPFW/?tag=fabo03-20
This is the silicone that I used. It’s enough for 7-8 molds at least. It is a pain to get out of the port. Takes about 10-15 minutes to work it out. I use a Jorgensen style clamp to push on the intake side while pulling by hand on the valve side. I think a lower density silicone would be easier to get out, but this one works.
I really like the molds. Helps me visualize the whole port better.