I no longer have an A102.

Yes, my biggest concern with getting one of these is it will be unsatisfying. I am relatively new to the Hammond organ. I took piano lessons on and off, and have a Roland digital piano that my daughter mostly plays. About 5 years ago I was given a Hammond M3 that needed some work. I got it going and had it a couple of years before I sold it. I then picked up an A102. Very nice, and great in the right hands. However, I did not play it a lot, and I often went back and forth between the Hammond and the Roland D-50. I liked them both for different reasons. Bottom line I sold the Hammond. Not that I didn't like it, but it took up a lot of space and I could not justify keeping in in my mind for the amount I played it. I really like the sound, but again, it became a bit impractical. Maybe if I was retired and had more time to play it, it would have made much more sense to keep it. Anyway, with just the D-50, I thought I'd ask the question of how to still get the Hammond sound (doesn't need to be perfect) while using the D-50 as my keyboard.

I know this forum will be biased toward a real Hammond, but that's not the question I'm asking. I could get an M3 for free. It would be smaller and easier to find a place to put it, but I'm exploring the options with a module first.

That's fair enough. I would try out the B3X on your D50. If it's realistic enough for you, then that's probably the way to go. There are a lot of other hammond emulators out there, but none of them are perfect. If you want something very compact with a lot of other good sounds, you can try out Hammond's SK series keyboards. One of those might replace your D50.

Impressive, and impressive price!

I agree. I've played on both the Nord C2D and an SK1, and I think their Hammond simulation is pretty good, and both have outputs for a real Leslie.

The (blues) devil is in the detail. Are certain details important to a player. Are certain details important to a listener to a reproduction of a performance. Do details matter to achieve the best possible / inspirational performance. Do details matter when looking for a personal sound. Do details matter to someone who has no ear for details? How difficult is it to get a real Hammond up to standard so details can flourish?
----Listening to this Youtube video on my headphone : the Hammond sound is very useful because it's very balanced and transparant and nestles nicely and in an intimate sounding way in the midrange alongside the other instruments , with no special details of overdrive / grit of the highest frequencies of the instrument , but some nice useful touches of overdrive in the lower midrange on a few occasions (at 0:10 is the first touch , although if one listens very carefully there is also some chair or something sqeaking which actually is maybe fooling me into hearing a moment of overdrive , ....on a third listening I hear it is actually the bass is causing it! The magic of instruments coming together in a split second.....at 0:38 some overdrive, ... at 1:00 clearer example of some modest overdrive higher up the frequency range, not your typical lowmid growl).
It sounds warm / intimate.
I don't think the solo sound is something special at all , it is probably better balanced than a lot of mediocre Hammonds but it is not the top-notch quality that can be achieved with a real one. Not as fat , but most of all not the intricate complex attack of a real one (with some crispyness still left in it ) well recorded , and no (remarkable) overdrive at all in this solosound. Fuller organ that follows the solo sounds warm but also somewhat plastic. Maybe also because you would normally expect some more volume from a real Leslie when switching from solo sound to a more full organ.
The drawbarsetting with the 1ft (fully) open setting sounds nice and (very) clean and works well. Many Hammonds with uneven volume in the last 15 wheels , or overall dull sound , surely won't render that as smooth and clear.
Conclusion : this sound does a very "decent" standard accompaniment job with a convincing intimate/warm smoothed out / hyperequalized tone. (Listening to the following clip of the same band ("You got me") it sounds okay (although already less convincing/thinner/more plastic) , but again it plays a relatively subservient role.
Dynamically it all sounds pretty flat , but that's no real problem in this standard accompanying role. This sound only allows me to dive into it to a certain point , after that there is a hedge which says....not able to dive any further ...sorry!!
I dont know how good the Leslie impersonators are (Ventilator) in their overdrive. I don't hear the extremer overdrive levels to judge wether this is a real Leslie. It has the convincing intimacy of a close recorded Leslie , the stereo is not very wide or open however. Panned to one side.

I like how Jimi Hendrix expanded blues to something next psychedelic level with his feedback.

EDIT : I now see in the video that he is using a real Leslie !! Is that one a hybrid tube / transistor standing there in the corner?? Is that the 760 transistor? Could be , there's hardly any overdrive in the lowmid. But it's a pretty warm sound.

My guess is he generally prefers 2 5 octave manuals , and a tube preamp and a tube Leslie that he completely serviced up to spec. I serviced many Rhodes satisfactory , but not being a good pianist.
Being able to construct the best possible camera and having all the knowledge of lenses and light , doesn't mean that your ambition is to be a famous film director. But the famous film director will pick the technicians brain endlessly because he is fascinated by the inner workings also , because it will enable him to have more control over the aesthetics of the endproduct.