Deciding on the scaling method should really be one of the first things you do when starting out developing a game on Corona. Changing it later on in the project may take a lot of work.
One thing you could do is use bitmap fonts, but I’m not really sure if you can position them accurately with zoomStretch if the scaling distorts the diamond frame. There’s probably some formula to figure out for offsetting images based on the amount of distortion, but I don’t use that particular mode and I don’t want to figure it out 