Looks good, but it might be better if you can sort username to the first displayed name in list of merit senders in each posts/ threads. I think it is what users ask for. For small posts/ threads, that received unsignificant merits, it does not matter. Nevertheless, for huge posts/ threads, that received hundreds of merits from many users, if you only merited minor merits (one, two, three, example) your name will be listed and bolded in very last position. So, current version of your userscript will not help too much.