I've tried using pectin in a pastry cream recipe and it didn't work. I followed the recipe so maybe the recipe was whacky. Came out runny. Bah.
I don't like agar. It's big in the veg world, but every time I've tried to use it, it didn't work. I used in to make Bavarian domes for one of my final projects in school and it barely made a difference between the domes that didn't contain it. It is so difficult to dissolve. I tried it in pastillage and that didn't work either. Plus that stuff is so expensive! They sell it for dirt cheap in Chinese grocery stores, but no in flake form. It's straight out of the ocean seaweed looking and it would take forever to grind.