Hi,
As far as I know, the TG launcher had only one version - with a drum for 8 rockets.
Bf 110 V19 (BB+AK, W.Nr. 2656) wasn't equipped with a TG, but with 12 separate EG (Einzelgeraet) launchers, for just one projectile each (and so not an improved version), mounted in two rows (7+5) under the fuselage and covered by a fairing in a form of a huge gondola. You can see a picture of the launchers with the fairing removed here: http://www.net.bialystok.pl/~hess/r_lpn_rz65.htm , there's also a schematic drawing of the TG (but I'm not sure if the link works at the moment 
).
I also know about a Bf 110 NE+AC used for RZ 65 tests, but I have no idea about it's identity. There was also a Bf 110 equipped with a single EG launcher under its rear fuselage, shooting left, perpendicularly to the flight direction - it's said to be an E-2 aircraft, but I'm not sure (maybe the V19 again?).
Kind regards
Grzesio