Avast Thar Matey,
Aye will do the best that Aye can for a fellow Marc.
1. Recommend reading this document http://www.smartrigger.com/downloads/SmartriggerUsersGuideNov04.pdf
to get the answer to the PD-7 to TD-20 issue.
2. Aye have several pads setup for snares, two pads (one right hand, one left hand) for hits another for rim shots and yet another for rolls. I don't get any machine gunning at all.
3. The TD-20 has a sound for a snare roll and it is editable as far as duration is concerned.
4. You would have to change your Zendrum to match the midi channel for those sounds. If you have a Z3 it means you have to change the entire Zendrum. If you have a Z4 you can change the MIDI channel on each pad individually. Once you decide which way to go (depending on your zendrum version, setting up the MIDI notes is as easy as looking up a general MIDI Note map on the Internet and programming it into the Zendrum on any setup number you choose.
5. See 4 above.
6. Aye have several percussion instruments setup on my TD-20. On the TD-20 use the rotary wheel to go to number 50 (user setup). On the Zendrum, go to No selection on the data pad. On the TD-20 press the buttom labeled "INSTRUMENT". On the TD-20, strike the pad you want to set, then back on the TD-20 use the menu buttons to go to the instrument list and use the scroll wheel to go through the list of available sounds. Strike the selected pad on the Zendrum again to ensure you are getting the right sounds from that pad. Set up the remaining pads on the Zendrum the same way and you will have a complete map for TD-20 User setup number 50. Don't forget to save the setup on the TD-20 and on the Zendrum.
Since Aye know nothing of melodic stuff I don't have anything like that programmed in. I do know the TD-20 has the capability of programming in short loops. Aye recommend reading the TD-20 manual about this capability. Those loops can be programmed to play either continuously or one note per pad strike.
I hope this helps.
Fair Winds and Following Seas,
Marc aka Pyrate