Noah ; first to answer your last question, 28.5" is not the perfect VSL. If it were that would be all that would be available. There are some folks that not afraid of changing strings, they just don't want to bother with it for various reasons. That is good for a few of us to make a few bucks doing it for them.
If you're able to tune your melody [.012] string to the g above middle c without breaking you're having pretty good luck, most break around there. You also are putting a bit of strain on your MD by doing it, the tension is about 3 times the rest of the strings. It would also help if you could sort out your use of 'modes', 'keys', 'string tuning' and 'overall tuning' for us. Basically;
A mode is an 8 [7?] note scale defined by the configuration of steps/half steps between the adjacent notes. The Ionian scale starts on the 3rd fret and has nothing to do with the tuning.
A major key is an 8 [7?] note scale using the Ionion mode configuration. The Aeolion mode describes one of the minor scales, etc.
A string tuning is the open string tuning of a single string.
Overall tuning is the open string tuning of all the strings to achieve a particular sound or capability. These are called 'modal tunings or just 'tunings'.