They look awesome! I'm still working up the courage to do a salt batch in a log mould so I can play with a swirl more. I've only used single cavity moulds because I'm chicken of cutting them. If I ever try it I hope mine turn out as well as yours did.
I love making salt bars and make quite a lot of them. I use a slab mold with dividers. I find I can slide them right out of the mold after about 2 1/2-3 or so hours. No trimming or hassle. I've used my log mold without too much trouble but prefer the other or individual silicone molds.
I will look into better moulds! For right now I cleaned them up by shaving the sides with a small serrated kitchen knife and then an exfoliating cloth under running water. It took ages but I'm happy with them! I left one small edge rough I liked the look. A couple of them look like kelp