Hi Emma, long time, finally the forum is back hein?
They love all opuntias, ofcourse the spineless varieties are the preferred ones, BUT they eat well the spines ones
they cope really well, with the spines, usually we get worried, but they are used to it
in either case to younger torts you can easily lightly flame the cactus and all the glochides (spines) will be burnt off and then you chop everything up and mix with all the other weeds