Although I'm and L&D nurse now, I got all my hours as a volunteer bf group leader & sat for the exam during nursing school.
You are right to refer to the
IBLCE directly for your information. Most people I know took 4-5 years at a minimum to acrue the hours and education needed to sit the exam. You could also maybe ask your question on the
Lactnet listserv (be specific that you have already looked at the IBLCE info & that you were looking on specifics on how people kept track of/ calculated their hours). There is also a YahooGroup,
IBCLC2B that you may be interested in.
Also be careful with the CLC vs. IBCLC designation; as you probably already know there is a confusing alphabet soup & you probably already also know that some people who take various courses or training, the week type course, etc. call themselves CLC's. For example, in my town the WIC breastfeeding coordinator calls herself a CLC (and is very knowledgeable in fact). But only IBCLC's have actually sat the board exam.
Anyway, best wishes! There are lots of great books, conferences, etc. out there to continue learning from (I learn more all the time)