Left the seat pan on the back burner while beginning the tank, and that starts with a plug that a female mold will be constructed from. I'll use 2 part foam mix from Tap Plastics that I'll pour into a hastily made box with a channel build into it to help define the underside of the tank where it wraps around the frame backbone.
The foam cures within minutes while expanding quite a bit so I mix it in smaller turds to take up the space in the box (that's been prepped with tape and PVA for easier releasing)
And here it is, just waiting to get shaped. My friend Pepe thinks it looks great as is. I'm inclined to agree...sometimes it's better to leave things as they are: approaching perfection as opposed to taking them too far. It's actually a point of tireless anguish among all great sculptors.