From what you've just written I can see you haven't understood my method at all, there is a good chance I haven't explained myself properly so I will try again.
before I do though I will explain why I know this works, 2 months ago I was always struggling to get pokeballs and had too many potions, a few weeks later I had no potions but massive amount of pokeballs and I wasn't able to get the right balance. Since using my current method I do not run out of any items and am able to lee my bag almost full (I've expanded bag space to 450 items) and if I use too many of an item in a short time then I can pick up those items again in a short amount of time.
however at the start it is not a quick fix, depending on what item you need I would either recommend reducing the amount of Pokemon you catch if you need more balls or not hitting gyms for a day or 2 if you need potions.
Ok so first step is to work out what items you need, let's assume it's ultraballs, if you start with 0 ultra balls from my own data whenever I had no ultraballs my pick up rate was about 5% but increased to about 10% after picking up a few. Usually when hitting pokestops you find lots of Pokemon, try not to catch too many and if there is a high level one you really want then try to use pokeballs instead (you want a good number of pokeballs in bag, too many and the stops give you mainly regular pokeballs and if you have too few pokeballs then the amount f potions/revives/razz berries may impact what drops from stops)
Note that you will (almost) always get more of the basic type of the item than the highest tier ball or potion but it's the ratio that this method massively improves. I'm not claiming that by only having max potions and ultra balls will just give those items but it will give you a better ratio of top tier items that makes it possible to keep a good supply of each item that makes sure you will not run out.
Finally, your turn either try it or don't try it I don't really care but for anyone struggling to keep hold of certain items it's got to be worth a try, for me it works really well and has been working long enough to be beyond random chance