It seems like the G2 has a limit of 60 MIDI Send Modules per slot. But you can work around that limit by placing more MIDI modules in another slot and routing them to the first one.

MIDI can send about 1000 informations per second. Having about 250 MIDI modules in all four slots (4x60) would slow down each MIDI module to 4 informations per second.

Another nice thing you can do is to make a midi-controller (by placing a bunch of controller send modules) assign those to your favourite hard/software synth and.... assign morph-groups! ALL your synths (hard or software) now can have morph-groups!

If your synth doesn't have that already (like Cameleon 5000): all your synths can now have -via MIDI - modulations in the audio range, like cross-modulation.

You've got to discriminate between MIDI that sent out physically or internally. Channels 1-16 and "This" refer to the physical MIDI output of your G2. "This" is a shortcut to the channel the slot you're in is sending/receiving. If you try to send on "this" and receive on "this" in the same patch, nothing happens because "this" refers to the channel of the external midi connection.

"Slot A-D" are internal MIDI channels. You can compare this to the other internal routings.