No expert on this end but a couple things come to mind in trying to solve this issue. One is that reference disk, just make sure the music on it is similar to what you doing in your mixes and is in line with what you hope to produce.
Two - Figure this is a big time challenge and accept it as such. I was fighting this very thing when I sent a song to a person that I was almost certain would play it through notebook speakers. Sure enough they did exactly that. When I played the song on my notebook speakers it sounded like a tin can. So what is one to do? Well, you could see this as a testing ground opportunity. You probably have 2 playback monitor targets in your studio. One being your monitors and the other your headphones. Add to that possibly a notebook, the car system, maybe a home audio system and a couple more you might have available to you. This many playback devices gives you a pretty good testing ground to try and shoot for. Don’t forget to use the volume knob on those targets to try and even out that variable. In the end if you want it to sound the best it can on multiple playback devices you need to test them on such and tweak accordingly.
Good luck!
LB