As it's two years since I wrote this article (and as I've just published my book on platinum printing), I thought it may be worthwhile to add a final comment here.
In the time since I wrote this article I have further developed and refined my printing process. While I'm still mostly happy with what I wrote, there are a number of techniques in it which I'd no longer recommend - mainly in the coating and processing steps. For example, I've found that citric acid is too harsh to use as a clearing agent for my favourite paper which is Buxton. I'd now recommend using an EDTA-based clearing process.
I'm always happy to chat about platinum printing, so if you'd like further information then feel free to drop me an email. Alternatively you can make my day and buy my book