First of all, I wouldn?t bother with the retaining bolts, unless the tips are quite loose which I doubt. The inner main tip is always going to be hotter than the outer extension tip. I?ve used them for dozens of flights and never lost one.
I use them for short summer flights around Arizona and they are effective. It seems that it is on climb and descent where the temperature difference is most felt. I don?t use them in winter or long flights, hence not having to deal with the retaining bolts is nice. I carry them with me to OSH, but just use them on the last hot leg back into PHX. I slip them on at the last fuel stop.