this is a vintage pattern that I have adapted
I had 2ply cotton in my stash that I used with a 2 mm hook and this appeared to work. Even given that I am much larger than the size in the pattern.
There is no support at all and the placement of the straps was a little out. The straps wrap around the back and are then fastened at the front with some buttons. There were no exact instructions about this in the pattern but I think it works OK.
I reduced the stitch and did half trebles and not trebles and even so the fabric is a little lacy or open when compared to the original.
I made this for fun and to see if I could make this.