so, i'm really new to this diy thing. i've been a cook and a mechanic for years, so i do enjoy doing things myself. i finally got ahold of some 50mg vg base nic, and figured i'd add some to some existing stuff that's a bit weak for me. 24mg seems to be my sweet spot, but i wanna make sure i'm not gonna turn some 12mg into 40mg and OD myself. is there a pretty basic calculation for this?