The building blocks of manufacturing - minerals

One question that I've been wondering about for a few days now i'm looking into manufacturing as an income stream - where do people get their minerals from ?

As far as I see it, theres 4 main ways of getting them:

1) Mining for yourself
2) Placing speculative buy orders at lower than sellers rates
3) Buying at sellers rates
4) Reprocessing item drops from missions

At the moment, i'm mainly doing 4) at the moment, I've been stockpiling minerals for a while, but as I'm trying to get away from doing missions as my main form of income, thats going to dry up if this goes well. 1) is a very slow option, and I can't imagine it will get enough solo to be able to cope with demand for materials in a high volume manufacturing setup - but when starting up, it's a great way of getting minerals, but I'd be wanting to work towards a Hulk ASAP, which is now a bit lower on my plans.

At the moment, I am doing number 2) - I have placed orders for about 80 million isk worth of materials at a major mission hub, hoping to get some of the unwanted minerals that mission runners get - problem is after getting about 0.1% of the materials in after a day, I realised a critical flaw in my plan - anyone who has bothered to train up refining enough to make it worth more than selling the mods themselves directly is probably stockpiling the materials themselves for their own use, and as such won't be selling the ground down items.

I may have to begin instead to place buy orders for the parts that are common mission drops instead and then reprocess them myself - problem with this of course is that because of the large number of individual items, I'm going to need a lot more training in my trade disciplines to be able to get enough orders out there to make it work - and then its a matter of managing all those orders to ensure that I'm competitive with the market rate so people will actually sell to me as well.

Ultimately, it seems the easiest way is to just buy minerals at the sellers rates, which are usually around 10% higher than the buyers rates, which directly relates to a 10% loss in potential profits. Is there anyone out there who does a lot of manufacture who uses this approach ? It seems self-defeating, especially with Tech 1 manufacture, where the profit margins are already razor thin in the first place.