I'd have to agree that writing Caz is pretty different from writing Remus. They have a lot of similarities, but I don't think Caz is quite as damaged in spirit as Remus. He's had a rough few years, but it seems he had a fairly privileged upbringing and used to think quite well of himself (he seems to think he wouldn't have given those pretty laundresses a second look before Gotorget, for example).

Of course, I may be making more out of the differences than is truly necessary -- as someone who didn't start shipping R/T until HBP, I think I write a darker-than-average Remus, heh.