Interesting to hear you talking about the thump Mike.
I've been following this thread because I have a 110flex coming from Harley; my perspective is slightly different because although I play bass...it's organ bass.
The thump, aka the "attack transient" is achieved on an electric organ by "kicking the bass". Tapping a bass pedal at the start of the note with your foot, whilst playing the bass line with your left hand.
This sounds best when the kick note is different to the bass note. And weirdly enough when the kick note doesn't change.
The thump is the volume so the note itself can be quite quiet.
Like playing double bass with a good drummer; the volume comes from the bass drum and your bass note "tunes" the bass drum.