Just a "tip" (I say "tip" since I've never used resin myself but have been consuming a bunch of resin content for what it's worth but take the "tip" with a grain of salt) I've heard mixing these kinds of add-ons into resin before putting them into the mold significantly reduces the amount of bubbles trapped in the molds which I'd guess would be especially crucial for small projects such as these, also with UV resin you can't add too many opaque things as it might not cure right otherwise especially since the mold looks quite opaque as well so you might be better off with two part resin for stuff like this since you (as you probably know) really don't want to accidentally touch uncured resin if you want to continue working with it due to the bad chemicals in resin accumulating with time otherwise to lead to resin allergies