I had the same problem you did with my lip balm, the shea got grainy, (even tried with Brambleberrys butter that they say does not get grainy, it does) then I switched to mango and it got grainy, they sold well because I marketed them as lightly exfoiation Ha Girls gotta do what she has to do (in fact keep getting order for it) Now I also make one similar to burt's bees, no shea or mango, I got it off of the PVS website, revised a little and I love it, not tight, not grainy, pure heaven. As for the tunneling, let them cool somewhat, top them off then hit the tubes lightly with a heat gun or blow dryer so that they seal together, if you don't do that the part you topped off with will just fall off bcz it is not melted with you original pour. HTH elle