fresh_vegie ~ I agree with BFS. Last cycle O was probably sometime from cd17 to cd19. That would make your lp 13-15 days long. So, yeah, I think your CHes are correct for this cycle and you could start expecting
today. Remember that it is within normal for the lp to vary up to 2 days so, assuming your lp is normally 15 days long,
may not show for another 2 days and you'd still be ok. I'm not sure how the paragard affects cycles. Copper is not an inert metal inside the body, though. I think it does have some sort of effect on things other than just the physical barrier to implantation.
echo ~ I don't recall there being any hard and fast rules about using the Rule of Thumb (ROT) to disregard outlying temps. I wish there were something like if it's more than 0.2 degrees higher or lower (although lower doesn't really matter) than all the other temps it can be disregarded. Anyway, the basic idea is to put your thumb above the group of lower temps and see if any of the temps are covered by your thumb. If so, you can use the ROT to disregard them. Obviously, a temp of 97.8 when all your other temps have been below 97.4 is an outlying temp and can be disregarded. Ovusoft will do it for you if you set it in your preferences. The ROT option is on the Temperature and Time tab.
dealic ~ It's normal to get fertile looking CF mid-lp and right before
. As long as you have a clear and sustained thermal shift you can continue to consider yourself safe.