Good question & thread!
I'm not sure SN is more toxic in individuals who have heart probs or who are anemia. Instead, I think the SN has more of a punch per gram, on those indivduals than those who are healthier. It's simliar to how skinny people only need to drink 20g's of SN compared to overweight people who prob need closer to 30gs'.
I was recently reading about something called the "Bohr Effect"
https://en.wikipedia.org/wiki/Bohr_effect which states:
"...an increase in CO2 results in a decrease in blood pH,[2] resulting in hemoglobin proteins releasing their load of oxygen."
Therefore I am thinking of increasing CO2 levels within my home when I CTB, via a gas tank. Also I think this might make my heart work faster / harder & since I personally have pre-existing heart probs. Basically I'm trying to re-create taking SN whilst stood on the top of Mount Everest. In that case, I would be highly surprised if I don't die by a heart attack before the SN gets me.
I also will be going on an iron diet in the weeks / days prior to taking SN, along with taking
Diuretics meds (which help dehyrdrate you via increasing the excretion of urine). Also I think smoking weed helps dehydrate & weakens you, along with increasing your heart rate when you get the inital high. So if you take SN straight after that when your heart rate is circa 100 BPM... well every little helps.
Then finally, & somewhat controversially, I will be spanking my monkey silly in the days leading up to taking SN again to further weaken myself as previously discussed here;
https://sanctioned-suicide.net/threads/masturbation-to-help-with-sn-ingestion.107206/#post-1841030 . Again to weaken myself & shed my body of as many nutirents / minerals etc as possible.
Of course all of the above is in addition to the meds recommended in Stan's guide.