Try to get a captive-bred Rainfordi/Court Jester if at all possible, as they've been raised to accept frozen foods like mysis and brine shrimp. I've frequently seen wild specimens come into a "local" (translation: ten-hour trip) fish store: they linger for a few days, and then usually die. I was going to buy one of these last Spring, but the poor fish was already floating dead in its tank when I came to take a look.I wish I can have utilitarian fish as you said but the options are very limited. I will look into the rainford goby (also known as court jester goby) but the thing is I'd have to pick between the YWG and the rainford. Also, have you had any first hand experience with the rainford? According to liveaquaria it's in the moderate difficulty category.
I'd go with a hardier fish; there are so many lovely goby species that are much easier to keep if you don't want to (or can't) maintain a specialized, individualized feeding schedule.