I have a suggestion if you would like a more modern feel...
Decide how big you want your quilt, then use solid white or tone on tone white to make up the remainder of that size. You can place your chunks of triangles where you want them, not necessarily symmetrical ( but that is ok too) the white in the negative space can be different sizes, whatever is pleasing to your eye! I can see it in my head, hope I am relaying what i mean so you can grasp it

I like the colors in your triangles, i just think the sashing fabric isn't working well with them...