You might have to use collision detection and the Cloth Room, which I think has a bit of a learning curve. I know that there tutorials on the adjusting clothes in the Cloth Room. I think that P5 intends for you to use the cloth room to fit clothes instead of simply trying to conform them (which was always problematic). You might also consider buying The Tailor at Daz3d, which goes about this whole problem from a different approach. It will allow you to transfer your figure morphs to the garment so that you can morph it to match the figure and get the physique you want. Good luck.