Just an update first:
To further check if the key combinations were being passed through correctly from the "slave-key" macro to the specific "/assist toonX" macro, I added a "/cast Lightning Bolt" to the "/assist toonX" macro and it works. So I made a "/cast insertspellhere" for each spell I wanted to use and put that in my "master bar" and it works too. I don't get what the difference is between A) a Lightning Bolt that has been dragged from the spellbook to the corresponding master-key, and B) a Lightning Bolt macro that says "/cast Lightning Bolt"...coz "B)" works but "A)" doesn't when they're essentially the same thing (?).
I also got rid of Super Duper Macro - it's doing some weird stuff with my macros.

With regards to the keyclone keymaps, I don't see anything wrong, try hard as I can with my newbie eyes. Below are the keymaps ("1" is the master-key and "u" is the slave-key):

Description: artaa
1 = t1b1
LCTRL+LALT+U = t2b1
LSHIFT+LALT+U = t3b1
LSHIFT+LCTRL+LALT+U = t4b1
LCTRL+U = t5b1

Description: artee
LSHIFT+LCTRL+U = t1b1
1 = t2b1
LSHIFT+LALT+U = t3b1
LSHIFT+LCTRL+LALT+U = t4b1
LCTRL+U = t5b1

Below are the macros (BT4Button85 thru to 89 are the "/assist toonX" macros, and BT4Button1 is "1" in-game):

artaa (bound to "u" on the slave bar):
Code:
/click [mod:CTRL,mod:ALT,nomod:SHIFT] BT4Button86
/click [nomod:CTRL,mod:ALT,mod:SHIFT] BT4Button87
/click [mod:CTRL,mod:ALT,mod:SHIFT] BT4Button88
/click [mod:CTRL,nomod:AlT,nomod:SHIFT] BT4Button89
/click BT4Button1
/targetlasttarget
artee (bound to "u" on the slave bar):
Code:
/click [mod:CTRL,nomod:ALT,mod:SHIFT] BT4Button85
/click [nomod:CTRL,mod:ALT,mod:SHIFT] BT4Button87
/click [mod:CTRL,mod:ALT,mod:SHIFT] BT4Button88
/click [mod:CTRL,nomod:AlT,nomod:SHIFT] BT4Button89
/click BT4Button1
/targetlasttarget
I omitted the "/click [modifiershere] BT4ButtonX" line to save on characters and it wouldn't matter would it? Since it only refers to the current active toon which tells it to assist itself? Or is this the reason why it's not doing what it's supposed to do? If so, damn the 255 character limit on the in-game macro!