I thought the latex mould should be entirely dry already, so I made the first soles using it. My first idea for removing air bubbles from the heels worked just fine. I pressed the heel closed, poured in some resin, released the heel, and checked it. There was a small air bubble inside it, so I tilted the mould a bit and squeezed the air out of the heel.
Then I released the heel again and this time it was full of resin, so I filled the rest of the mould.
The shape of the mould required building a support for it, so no resin would spill out.
And here is the finished casting. It is better to be able to make these with latex moulds as I only made two soles to get one pair of shoes. I don't make that many shoes for Rini, for whom these are intended, so it would be too expensive to use silicone for a mould for these.