Very excited to see this. I do a ton of sculpting with my side business at
www.wretchedhivecreations.com and have done several Cantina aliens. Bossk was always one of my favorites.
For the eyes, a trick I've used many times was to use acrylic Christmas ornaments from the craft store. They come clear and you can paint them from the inside so that they appear glossy and shiny on the outside. For Bossk you could do the red solid and use Testor's spray auto tint for the black. A few thin coats of that will give you the darkness you need but remain see-through enough to work. I did it on my Ponda Baba here:
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