A P-lip fits nicely between my molars. I only smoke bents, any degree, and do not clench, the pipe simply rests between my teeth, jaw at rest. A P-lip facilitates such and is very comfortable for me. Not much difference though for me between the "lip" and a properly executed "fish tail." Not a fan of the tiny (thinner) bits as they do not fit my style of smoking.
I smoke meers exclusively when at home and seriously doubt there is any health benefit to such. Although it does visually demonstrate some of what you are absorbing through your mucus membranes as you smoke. In my experience a quality meer colors in the stem and the bottom of the bowl first, as a rule. Some opine that a meer smokes "drier". I've not purchased a meer in 20+ years so cannot opine on the quality of today's products. I've never owned a pipe of African meerschaum so can only speak to the Turk's products.
I do not believe you are losing any of the poisons, so don't worry about not getting a quality smoke or reducing taste. I think most of what seeps into the meer is minimal and not reducing the smoker's enjoyment to any measurable degree.
