Yeah, the Detuner would need to be at a different angle to have a shot at being used on an E string in a 5 string setup. It's just big.
Another option (which is more expensive upfront) is to change the tuners to the Sperzel Lock-Tite ones. They also offer a detuner that attaches to a regular tuner, and looks to be much smaller, allowing you to possibly put one on the E string.