Minimum Flange Widths
In general for standard brake setups with an inside bend radius equal to the material thickness, the minimum flange width is 5-6X the material thickness.
For material that allows forming sharper bend radii, the minimum flange width can be reduced to 4X thickness.
Please note the minimum applies to the material both sides of the full length of a bend, and so applies equally to cutouts, large holes, and stepped or tapered edges.
Small holes can usually be closer to the bend, with varying distortion depending on the details.
Work in progress: adapt from "bend force chart 2.xls" to match up bend radius with material thickness, keyed for 1T