So from going from your example i should be able to do:

/target [mod:ctrl,mod:shift,nomod:alt,target=Tilce1]
[mod:ctrl,mod:alt,nomod:shift,target=Tilce2]
[mod:alt,mod:shift,nomod:ctrl,target=Tilce3]
[mod:ctrl,mod:alt,mod:shift,target=Tilce4]
/cast [mod:shift,target=focus,harm,nodead][harm,nodead] Lightning Bolt
/cast [nomod:shift,target=targettarget,harm,nodead][harm,nodead] Lightning Bolt
/targetlasttarget

or

/target [mod:ctrl,mod:shift,nomod:alt,target=Tilce1]
[mod:ctrl,mod:alt,nomod:shift,target=Tilce2]
[mod:alt,mod:shift,nomod:ctrl,target=Tilce3]
[mod:ctrl,mod:alt,mod:shift,target=Tilce4]
/cast [mod:shift,target=focus,harm,nodead][target=targettarget,harm,nodead] Lightning Bolt
/targetlasttarget
/target [mod:ctrl,mod:shift,nomod:alt,target=Tilce1]
[mod:ctrl,mod:alt,nomod:shift,target=Tilce2]
[mod:alt,mod:shift,nomod:ctrl,target=Tilce3]
[mod:ctrl,mod:alt,mod:shift,target=Tilce4]
/cast [mod:shift,target=focus,harm,nodead][target=targettarget,harm,nodead] Lightning Bolt
/targetlasttarget

This is the proper one, the first one would mess it up badly. :P

I would also suggest implementing this for purge then as well, so you can purge and then nuke your focus if you believe you have a second extra. Does add a gcd, but its doubtfull they'll catch on.



/cast [mod:shift,target=focus,harm,nodead][harm,nodead] Lightning Bolt
/cast [nomod:shift,target=targettarget,harm,nodead][harm,nodead] Lightning Bolt

In this case, [harm,nodead] is useless as you will have them target your main anyhow, which isn't harmful. So, go with the second. There's a lot of useless stuff in this one.