Can someone elaborate on that? Even I thought more GSM meant lesser bleedthrough/more FP friendly.
GSM is not the only criterion. The more the GSM, it is better. Opacity of paper, texture of paper, ink absorbency, properties of ink affects bleedthrough.
Certain papers even though having less gsm does not bleed through. whereas papers like BILT 85 GSM Bond paper is bleeding through for me. I am using a wet pen.
Best way to select a paper is through writing samples in it. You have to check before you buy.
Having disappointed with BILT 85 GSM Bond paper, i bought a brand called ARTREX 90 GSM A4 notebook which is not bleeding through. But there is a light see-through, that is ok in my opinion.
So, i suggest you try different papers with different inks in different pens to zero-in on the paper. My next trial is going to be in a Rhodia notebook.