I never tried a tilde. I got the character set from a font generation program called cv_fonted which is here:
The font data for character 126 is 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, so clearly that is blank. If you want a tilde either download cv_fonted and use the editor or make a guess and roll your own. This data is row-wise so here is a guess:
12481248
________ 0x00
________ 0x00
________ 0x00
_XX_____ 0x06
X__X__X_ 0x49
____XX__ 0x30
________ 0x00
________ 0x00
{0x00, 0x00, 0x00, 0x06, 0x49, 0x30, 0x00, 0x00}
There is a newer version of cv_fonted which, while it is a lot better, it doesn't have an 8x8 font which is what I wanted.