In answer to various folks' observations:
I don't think I'm overloading the nib, I found the rhythm of dipping quite pleasant to get into.
I'm doing my level best to prep the nibs well, following tutorials I've found online. For the most part the nibs seem to be coating themselves in ink pretty adequately, which as I understand it is the key thing.
My paper is awful, I freely admit that, but I'm on a very (very) tight budget so I may just have to live with indifferent paper stock for now.
Estefa, I'd be very grateful to see the video you're talking about, I don't think I've found that one yet.
As to what I can get locally - I have a very good local art shop which stocks Higgins Eternal, Pelikan 4001, I believe at least one iron gall black, and some sumi inks too - no idea if the sumi they carry would count as "decent" to a conoisseur. I know they *used* to do Diamine registrar's ink, which is an iron gall blue-black, but they stopped stocking Diamine colours a while ago so they may no longer have it. I can't remember if they carry Walker's Copperplate or whether I imagined it - if they do I almost certainly took one look at the price and dismissed it from consideration due to budget. Walker's is no better online, either - it comes out at about £10 including shipping to order 30ml, and I can't afford to buy in bigger quantities. Hence the tone of mild horror when I ask about having to buy the expensive stuff.
I don't have a problem with the mere presence of iron gall inks in my household, if I can manage not to put leaded petrol in my car I can manage not to ink up a fountain pen with acid, but purely for financial reasons it'd be nice not to have to keep two separate types of ink.
So far my experiments with gum arabic and water have yielded something more or less usable based on some Quink blue I had kicking around. Quink blue-black is something I've seen mentioned on FPN as being unusually good for pointed pens, too - is it particularly unique as fountain pen inks go?
But I'm running low on my blue Quink mix so coming up with something I can use longer-term is a very current project. It's sounding like I either keep on with the gum arabic thing, which is at least cheap even if it's a pain in the neck, or resign myself to having iron gall ink for dip use?