there are several versions of a DIY figrig in the DIY section...this is one that i made - super quick, easy, and cheap... http://www.dvxuser.com/V6/showthread.php?t=55021 there are others too...
another thing to do is try doing handheld with just your right thumb in the handstrap with the rest of your hand under the camera, using your left hand to steady...hold the camera down by your belly and look down into the viewfinder (instead of looking into it from behind)...
I'm not exactly sure how you are holding the camera or why the strap being too wide is an issue. If you are holding the the camera with your right hand, your right hand should go between the strap and the camera body. The weight of the camera can rest on your right palm, Your index finger should be able to reach the zoom rocker, and your thumb should be able to reach the record button. I also usually use my left palm to help support the camera with my thumb on the iris wheel, and fingers on the focus. Of course al long as the end result is what you want, there is no wrong way to handhold the camera.