On second thoughts, the tape is most likely okay. I'm with you on latex. I chose this Muc-Off sealent for its claims to being able to handle higher pressures, but so far it hasn't lived up to it.
You got an old spray bottle you can make some soapy water spray with? It was the only thing that clued me into the spoke leakage (bad tape issue) I had.
The tape is probably a good bet too, but latex doesn't work very well at road pressures in my experience