Hey there, i can tell you that if your making your own, you need a nice work bag durable, and around 220u, which is about 65lpi, or mesh. Then into a 110lpi or mesh would drop you down into a 150u, i would then try and get a 150lpi, which is around 70u. then into a 210lpi, or mesh which would be close to 45u, then finaly into a 300lpi, which would be closest to your 25u.
I would not sacrifice the fourth bag, it will improve your quality immensely.
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