Have you found a mould for your soap? I've been researching different ways to make molds and I've decided to get a setup to make lots of different custom molds. Basically they can be of any shape and size you want and the mold is made from a positive example of the bar you want. So I would need to make something that is the shape and size of the bar that you want and it can be made of clay, wood, foam, plastic (3d printed?) or even soap probably.
Say you had a rectangular bar but you wanted to have raised letters on the bar, the letters could be cut out of something else, or printed letters, or even letters from a craft store, and they are placed on top of the bar shape and secured. So then you have a prototype of what the bar looks like.
From there I can make plastic moulds, either individually or as sheets with whatever number of bars you want like grids of 2x4, 2x8, 2x12 4x1-12, 6x1-12 (for up to 72 bars per sheet), so there are a lot of options.
I've looked at so many soap moulds online and they are expensive for what you get and many of them don't hold up over time. If you are interested in this, please let me know b/c I'm going to start offering a bunch of custom moulds in the next few months.