If you're using that little tab that sticks out from the frame, where the coupler retaining clip goes, you could use an offset head coupler. These have the shank mounted lower on the backside of the coupler head, and will raise the coupling face. I think they're called underset shanks, and come in the usual three lengths.
There a few folks out there who say they can mount a standard #5 on anything, and have it come out the right height. A lot of time they're either shimming, or leaving out various bits to make it work. I think one person even shaved down that mounting tab, to get it to sit higher. Of course, he drilled and tapped the hole for a 2-56 machine screw.
Kennedy
thanks!