Flash and large aperture is always a challenge... You can do a few things... lower the flash power, which you did, you can move the light source away, which will reduce the light... Moving the light as little as a foot away, depending on the location of the light, may reflect a large drop of light especially since your light is already modified. You can drop the ISO to Low (50), which I do... ND filters is another way to go, but then it makes it harder to view in the VF... Some other factors... Use a large softbox so the light disperses even more in the softbox... then you can even move the light back some and have the same size catch lights but much more dramatic change... Erm... You can put more white sheer fabric on the softbox so the light has more diffusion to go through (less light), but watch the weight as it may make the softbox for top-heavy... Anyways I hope this helps.... It's usually pretty rare when people want less power from strobes, but it does happen from time to time, so I hope this helps.