Aloha P,
In the mid to late 60’s while in my Kenny Burrell mode (Jimi Hendrix was just coming on the scene)
I did stints with Jimmy Smith, Jimmy McGriff, Jack McDuff and ‘Groove’ Holmes,
So I know how ‘picky’ organist can be about their sound.
While most of these guys wanted their sound to be ‘smooth’, Jack McDuff was going for
that Jon Lord sound (tho’ I did not know of Deep Purple at that time).
Problem was altho’ he could get it (or close to it) in the right hand, the ‘crunch’ would also
be in the left hand where (contrary to belief) most of the bass sound was played. (not the pedals)
A lil fact:
All of these guys rarely used the pedals except when either ‘showing off’ or
mainly in ballads. 99% of jazz organ bass sounds are done in the left hand.
Bottom line is I really know that B/C3 sound and IMHO no plug has what I remember in my head.
That being said:
give this one a listen. Not very expensive and can go from ‘clean’ to ‘dirty’ with no probs.
http://www.genuinesoundware.com/?a=showproduct&b=24
Leslie sounds.
Now that’s a whole other thread. Jimmy McGriff used two Leslies and had some sort of
contraption that would ‘sync’ the two. It rarely worked but when it did it was amazing!
Anyone remember the Yamaha Leslie? With the three moving speakers? I still have one in storage. 
Good Luck!
{‘-’}