I've not been keeping this thread as up to date as I should be, but I've been writing it all down in my fishy notebook so I'm still keeping track.
I've adopted a new strategy in order to keep me sane. I'm currently doing daily 20L water changes. This is usually enough to get the nitrates down somewhere into the orange zone, so I know that when I test the next day and they're red, nitrite has been processing even though it doesn't appear to be going anywhere.
Of course, now I'm thinking that if I'm doing water changes every day anyway, I might as well get fish and complete the rest of my cycle fish-in. A 20L water change was enough just now to get my 5ppm nitrite down to 0.5ppm, so I'm sure that it'd do the trick to get a 0.25ppm close enough to zero.
I don't think I'm that impatient yet, and I don't have plants or food yet, but I'm going to the LFS either tomorrow or Thursday for some other things and the temptation is gonna be horrible!
NOT gonna get fish yet, because I'll regret it. Nitrite was in readable territory tonight (whereas it wasn't this morning) even though it was high, so hopefully it's getting there.