For modelling chocolate, I just use the back of either my dresden tool or metal ball tool to blend. Depends on the size of seam. Definitely my #1 tools. Occasionally I add a smidge of shortening to the seam, then blend till it disappears. I think this is a tip I may have picked up from Zoe Hopkinson..aka Zoe’s fancy cakes.
-- Creativity is God's gift to us. Using our creativity is our gift back to God. Clarky's Cakes 😎
I find if you use the heat of your hands gently as you rub the seam away works best. This a little more time consuming, but completely worth doing. Hope this helps ~ Bobbie
-- Bobbie Bakes
I get some Mc roll it into a ball, put cling film around it tightly so the cling film excess is at the back and I use the front to gently smooth all over the surface, it’s a great method for large areas.. keeping it taught..