The instrument itself has an importance.
I have several GK equipped guitars. One of them, a baritone extended luthier made swamp ash body GM like guitar is especially yielding good results.
Though Roland stuff (VG-99 for it's non midi functions) is not supposed to work under C# below std low E, in that case, it works with this guitar -and this one only- while it is tuned in C.
Others, tuned to C will only garble and then produce reliable sound when reaching that C#.
some additional 2 cents.
my little apportation to this thread is that you should know that some devices detect more ghost notes tan others. I have the Casio MG-510 Midi guitar and it is slow and takes a lot of phantom notes. Sometimes I can hear those when you play a low E note on any MIDI guitar.
Maybe they are forgetting that the devices can be wrong when hearing (hear more the harmonics that the fundamental), and the easier solution is to put (before the detection process) a low pass filter to avoid that ghost notes. So that could be a benefit for those frenquently low notes that are detected an octave higher than the actual.
You can try to turn the guitar tone to 0 and the use an octaver, and you will see how the effect has a better response, and also for the guitar or bass setups a darker tone, and the neck pickup, helps the tuner detects the main frequencies better!