Carbon has 15 isotopes , 13 of which are radioactive and only one of those has a half- life long enough to be considered useful in mass measurements, water flow, deposits of chemical fossils, and time determination. What are you talking about?.
Look up NMR and the determination of ratios of C12/C13/C14 in samples, its a mature technique
Youre kinda playin in my court mark.
BTW, C11 has a half life of about 20.3 (+/- 0.45) minutes.
I dont know where you yank some of your musings, most of which is gibberish. Ill give you two sources that are written in a popular vein for non- scientists to njoy.
1. The Geosciences HAndbook-AGI DATA SHEETS, 5th ed. (AGI pub)
2. Radiometric Dating--A Christian Perspective Wiens, Roger.1994,(expanded 2004).
PS, If C14 ws "birthed" today, I dont think any reasonably competent scientist would waste lab time and expense to measure hqlf lives or remaining isotope. Wed probably just read the newspaper as to what caused the cosmogenic "injection" of C14 " on that day. If you want to determine the amount of C12/C13/C15 (and all the rest ,most of which have half lives in milliseconds,)except C11