Creighton user here, and a bit of a Creighton cheerleader. If you think switching methods would be best and easiest for you, then that is your decision to make, but I truly think that Creighton offers a solution to most women struggling with most issues relating to their observations.
I have a friend who has had a personality clash with her Creighton instructor, and she has a much different level of satisfaction with the method than I do--so I talked to my instructor (in a different city) to get a recommendation of a good instructor near my friend. If you go to fertilitycare.org and look for one of the 'major' FertilityCare centers in your region, even if it's a few states away (or call the Pope Paul VI Institute in Nebraska), and they should be able to recommend other practitioners/instructors for you. Don't feel bad about it--if you don't click, you don't click. It's like any other medical professional--you should trust them and their abilities, and appreciate their "bedside manner". If you need to switch, you need to switch.
I have wacky cycles (probably PCOS, endo, thyroid problems...) and occasionally use the yellow stamps. When we first incorporated the yellow stamps my instructor did show me the picture book that agape mentioned. It's very helpful. Even if you don't meet with your instructor in person, they should be able to mail it to you for a little bit for you to look through. Some other suggestions that have helped me...
When thinking about sensation, ask yourself if it REALLY is lubricative. Sometimes just because I've been in a seeming holding pattern of lubricative CM, I get a little lazy and just assume that it always feels lubricative. Sometimes it's just smooth--which is a whole different story.
Along with the point of change thing, your instructor should be having you ask the question "Is this CM essentially the same or is it essentially different from yesterday's observations?". That helps point out the point of change more clearly. I put Ys and Ns on my chart for each day to show that I've asked, and then a little up arrow on the point of change day. I'm guessing that's standard CrMs charting practice.
When I started dealing with constant mucus and trying to chart, my instructor recommended a variety of changes to living habits and supplements. Of course ask your instructor if any of these are appropriate, but here's what I did:
Started taking 1000mg of Vitamin C daily. This reduces mucus so that you are only observing peak-type and the non-peak-type goes away. At least that is what it did for me.
Changed bath soap and laundry detergent to "no fragrance/color added" versions. I now use Dove Sensitive Skin bars in the shower, and any brand of "free & clear" detergent. I also ditched fabric softener for towels and undies, and when I do use the dryer sheets I use the no-fragrance kind. All of these soaps/scents/colors can alter your body's chemistry and affect the CM observation. It sounds weird, but it really has helped!
Similarly, feminine hygiene products can cause CM observation problems. Definitely avoid any scented/deodorant pads and tampons. I also avoid the brands of pads that have a more plasticky feel to them, as they don't allow air flow. Also only use natural personal lubricants (virgin coconut oil works great; a sheet I got from my FertilityCare center recommended olive oil or SHORTENING, which grosses me out!) and never douche (this is one of the tenets of CrMS anyway...the whole 'the vagina is a self-cleaning organ' element of instruction)
Wear only cotton undies and avoid pantyhose (or remove the panel in the crotch area, if possible). Sounds weird, but it's related to the whole 'breathing' thing, too.
If I think of anything else that might help I'll post it. Sorry for the long post--I hope you figure things out! From what I've heard navigating post-partum can be so difficult, and to be honest difficulty in identifying truly infertile days was one of the reasons we started TTC over a year ago. (For me the use of yellow stamps indicated other issues and sub-fertility, though I know that's not how it works post-partum.) Good luck!