I’ve been playing left hand bass and right hand keys for a few years now. I notice no real issues. A couple of tips I’d pass on though are to ensure your bass VST can provide legato transitioning between notes; mostly have it set to mono mode and never use a sustain pedal. For slower songs I set the release parameter of the sound to a bit longer. I also sometimes set the attack to be a little later than key strike…mebbe up to about 1.4-1.8 ms
But it is a lot of fun playing your own basslines to match what you are doing in the keys side of things!
Hey Dennis
Yeah, I do some of the same things, in fact, I provided bass/keys at a gig last night. I certainly agree with your tips. I was commenting on the video above, and to get a decent “realistic” bass emulation (as in the video), parameter adjustments throughout a song would be quite a challenge, especially if you are also providing key sounds at the same time. I also think back to my Hammond Pedal Board experience (which I never really mastered), and know how difficult it can be for most people. I just think using the bass plugin above, as in the video, and while also playing keys, would be be better suited for an Octopus. 
I have to think that really… if you’re going for left hand bass it’s probably better to just go for a pedal or synth type sound and not emulate a bass guitar incompletely. YMMV of course but John Paul Jones, Ray Manzarek, Keith Emerson, lots and lots of jazz organists and others have all made that sound just fine, whereas if you’re playing a bass guitar sound but not quite hitting all the subtle slides and fret noises and such a bass player does you just get an uncanny valley situation where a listener thinks, eh- something’s off.
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Absolutely!! I normally use lower octave Hammond sound…works just great…at least for the trash I play. 
Actually with after-touch and velocity triggered “noise” samples it’s pretty easy really. You just gotta get the right VST to start with then it’s a bit of technique learning.
I personally see no problem with using an instrument that “sounds” like the instrument you want to play…
After all if you cannot lug a B3 around, why not just use a GM organ or a synth emulation 
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Because it’s a keyboard emulating a keyboard, that’s why it doesn’t require a host of extra controllers to emulate functions and behavior that isn’t native to a keyboard at all.
Exactly my thoughts. The VB3 pedals layered on to the first 25 keys is a bass sound that works well for me. It’s familiar, solid sounding, keys friendly and neutral in a good way (as in not uncanny valley). I’ve been listening to a lot good B3 “bass players” (Reuben Wilson is my favorite) who can comp and solo above their lines. Most of the bass action is left hand but I think they use the pedals to add a little oomph here and there and to get them through Leslie switching. Maybe it works for me because I’ve been practicing - right hand comping is working but I should probably just forget the soloing 