would be the 'assist macro' say you put this under T.
yes it would be. But you can't (or better shouldm't) use the way you did it, presented above.
Simple reason why:
<Hotkey 1>
<Passthrough>
<If ActiveWinIs wow1>
<SendLabel Alt1, Alt2, Alt3, Alt4>
<Key %Trigger%><Key rctrl rshift T>
..this comes down to 1 userkeypressing resulting in 2 different client-keypresses, and this is seen as automation. So never ever do that!

What you can do instead, to simplify setup time is:
-use '/click ActionButton' in your macros instead of the hole '/asist [mod....]'-sequence and also the general setup uses different master and slave keys, this is not mandatory, you can use the same, so that you for every targetet spell only need one macro..

For me this comes down to round about 5-6 macros per toon, which is not so much

If you have any questions fell free to ask!
I think, Anemo (or perhaps I, if he doesn't want to) will in the future write the hole concept and variations up in the wiki, so take a look there (in some days).
Or if it helps, i could also send you my hkn-file, which you then can customize...