I live in goat head territory (NM) and struggled with tire liners for a while. I was never satisfied with how I was able to install them. In frustration I glued them in with some 3M super 77 with talc on the tubes. Another time I stuck them in with some double sided scotch tape. Both ways worked good except the liners didn't stop the goatheads.

I gave up on all of that and for the last few years I've just used cheap 100 psi Cheng Shin tires and cheap tubes with some slime. The 3 or 4 hours a week I sometimes spent dealing with flats is now additional time spent happily pedaling my bike.