Hi there, did you ever manage to find success with the bust reduction? I ask because I have experimented with this very thing -- so far, I have only found ways to do it for figures that will be at least semi-clothed on permanent basis, as it requires permanently 'damaging' the tbleague body. My method is to figure out how much of a reduction you want, and then simply take an exacto knife and cut away that amount from the base of each breast. Then, to press it back into place, I use saran wrap/cling film, which can be taped closed at the back of the figure with very small piece of double-sided tape. I first attempted to glue the breasts back down at the base, but sadly I have not found a type of glue that works yet, hence the use of the cling film. If you only wrap them lightly, then they may still 'stick out' a bit, but if you wrap them tightly, it will give a more flat-chested appearance.
This SHOULD work under clothing -- just be VERY careful when cutting under the breasts. You will have to make TWO cuts to each breast. The first should be at the base, where the breast meets the torso underneath. Don't cut too deep downward, as you could puncture the chest/body cavity underneath. Also, don't cut too far up the sides of each breast, in case you want to still be able to show some 'cleavage' on the figure. The second cut will be above the first, creating a sort of 'slice' or 'wedge', which you then remove from the bottom of the breast. Cut slowly and carefully, as the silicone can be tricky. How much you remove, aka how big of a 'slice', is up to you. I found that, on the s25b, even just removing a small sliver was enough to make the bust look a bit more natural. Obviously, try to keep the 'slices' evenly shaped. It may help to first draw the lines where you plan to cut onto the tbleague body using a pen prior to actually making the cuts.
I don't have photos yet, as the first time I tried this, I didn't think to take any and now the figure in question is essentially sewn into her clothes, lol. But when I do it again, I'll share some here if anyone is interested. : )