I'm curious to know if you were in need of the last rites and no Resistance priest was available would you accept an SSPX priest to administer the last rites to you? Or where do you draw the line?
I draw the line the same way the Church has ALWAYS drawn the line.
The Church allows for receiving even the Sacraments of Schismatic and defrocked priests when in danger of death.
But you are hardly in danger of death most of the time when deciding to drive to your local SSPX Mass an hour away rather than three hours for your resistance Mass, now are you?