A baritone scale length with Fishman fluence moderns and a hard tail bridge?
Don’t know too much about crazy down tuning tho, but if you are going to change tunings radically maybe 2 guitars is what you would need, the tension changes on the neck even with a fixed bridge isn’t great.
Edit by drop a do you mean Aadgbe? Or Aeadgb? Cuz either way you will have a real hard time going back and forth imo. If your guitar is setup for one tuning the strings will get crazy floppy when down tuned. Or too tight to up tune.
I could be wrong tho, I go from standard to drop d on one guitar and d standard to drop c on the other. But in my experience just going from standard down a whole step to d standard (Dgcfad) was too floppy for one guitar.