CPI exam – how long did you actually need to study?

I've been working in clinical research for about two years and my institution is pushing us to get the CPI credential. I'm trying to figure out a realistic timeline. Some colleagues said 6 weeks was enough, others said they needed 4 months.

My background is mostly regulatory – IRB submissions, consent documentation, adverse event reporting. I'm less confident on the financial conflict of interest sections and the international research ethics content. Those feel like deliberate gaps I need to close.

I've been doing about 2 hours on weekday evenings. If that pace holds I figure I can get through the PRIM&R materials plus some supplemental reading in about 8 weeks. Does that sound realistic to people who've done this recently?

Also wondering how heavily the Belmont Report and CIOMS guidelines are actually tested versus being more background knowledge. My first full mock came back at 62% which felt rough.