hy francois, nice sheep

i am not a haas guy, but i can tell that you allready have some good experience with macros
if you wanna fast development, try finding persons that share lists of their own macros, and from there only pick those that seems interesting to you; thus look for description, not for code, and only based on description, decide if is needed to also investigate code; such an aproach will get you up to speed fast with custom variables
another thing to follow is to target code syntax, the way is written; this can help you with general formating, etc; just scroll through code, does not matter what that code does, but scan the way is constructed; for example, the code shared by seth checks if something is wrong, but you can skip such a check by controling the inputs, thus being sure that they are corect
once you reach control capability, and g-code langauge limitations, next step is a more general way of coding
books are being written by people like you; good luck
we.tl/t-0NeUrzjZ3E