Nobody has been able to stack enough perception to even begin to test this stat. It is broken as can be. I have double melded perception tools, hq gear for max perception and it still takes me a hours to get the items I am looking for. Then the next day I can get them back to back on first node, it is all classic SE RNG imo. I can wear a balanced gear set and achieve the same results.
A few other posts have gone over this topic. My two cents are that I debate the investment of my perception gear and the extra time it takes double tapping the rare item in the node are even worth it compared to a cheap balanced gear set that allows you to pull item in one swing. This is most noticeable while attempting to get Gold Ore +1. A friend of mine "tested" this out and due to me having to double tap the gold ore every time and he did not. For every three mining cycles (3 nodes) he got four cycles in. That is a big jump. That means he got 24 more attempts at gold ore +1 then I did in the same amount of time. I did get one more HQ gold ore then him in that amount of time (I got two he got one, again RNG) Granted not a scientific test but you get my point.