i am kinda wondering if a "fence line mower / trimmer" might be better. with the "arm" that causes entire trimming head to move around fence posts and like might be for a cemetery and like... though on other hand i could quickly see after a few times usage. find a build up or rather a 'smear mark' going across all the head stones.
other issue to double check is how easy it is to re-string unit. when ya get into the bigger string, it generally is not self feeding (bump on ground and more comes out) and you need to take a short piece of new string and put into it. that might be a big down side. use up a little bit of string on the end. and you no longer trim right up against things if it has an arm that causes trimming head to move in and out. (it would not be bad for a fence line, but for a cemetery, meh...)