Dread piratewes -
1) use the site search feature (upper right corner) to look for the word truncated See the third and fifth posts down on the hit list.
2) You could fill your small bag(s) with grains, tie them shut and put one or both in the mash step inside the bag that is too big. That way the smaller mesh of voile works in your favor and the larger bag with larger gaps still helps. Stirring mid-mash then becomes a matter of slow dunking of a small bag rather than actually stirring.

Drewadpiratewes - Whatever works for your kettle and process will give beer.

https://www.biabrewer.info/viewtopic.ph ... nce#p53465 has an old answer of mine regarding how to make a bag. In it I describe how my wife made mine without any taper. The full circle of voile (wider than the lid, diameter reduced by the seam) is the bottom of my cylindrical bag. The vertical part was a rectangle, not an arc. I do use a metal vegetable steamer placed on the kettle bottom for separation to avoid melting the bag. The height of the bag gets adjusted so that the bottom just touches the vegetable steamer. The diameter of the bag stretches slightly to wrap around the kettle rim and then binder clips hold it in place. The inside wings of the binder clips fold down (not wet in the mash) to allow the kettle lid to sit flat. 70+ brews later, the bag looks used, but still works. Oh, no - I've probably jinxed it now.

I believe that the thread count is a significant factor in success. Too coarse and particulates escape into the wort; too fine and draining becomes a problem (more so with rye malt). My local home brew shop continues to stock BIAB bags that have a too-low thread count.
I wish I had access to the analytical instruments that could detect tannins and prove my theory that hand-squeezing the bag of spent grains at below mash-out temperature doesn't extract any more than not squeezing. That deserves to be tested with multiple grain combinations and temperatures to be sure, but then the myth can die.

The short answer is 35 threads per centimeter. At the fabric store, the material is called voile. It is more often used as curtain sheers. I recognized it as the translucent curtains behind the window draperies at grandma’s house. It is not tuile- that’s for other stuff.

See this one for more general info: https://www.biabrewer.info/viewtopic.php?f=53&t=37

And I found the number 35/ cm coming from PistolPatch, so I know that’s good.
https://www.biabrewer.info/viewtopic.php?p=51849#p51849