Electrolyte Lick vs Tablet

My wife is a 53-year-old 185lb (down from 350lb in 2 years) Ironman athlete. She finished IM Lake Placid with no problem but DNF Maryland due to Hyponatremia. She will be doing IM Arizona in ~3 weeks. She is a bariatric surgery and cancer survivor whose diet we try to keep healthy but which is limited in quantity, thus the need for electrolyte supplements. She currently uses various drink powders and licking salts but the licking salts make her sick so she wants to try tablets instead. Our question is dose timing. I am of the (completely uneducated) opinion that licking salts enter the bloodstream almost immediately while buffered tablets take longer to deliver an equivalent dose. If this is correct, should the tablets be taken before her actual need, and if so by how much?