Help with charged spell

I'm trying the XE system, and did some basic missile spells, but now I'm getting a "writer's block" and can't think of a way to do my new spell:

- It can be charged for 2s.
- Each 0.5s increases damage by 30% of the caster's Int and the range by 100.
- Each 1s, a texttag with the message content (in order, being the last one said on finish) will be displayed over the caster head (just for players that can see the unit).
- At the begin, the missile must appear at the caster front, and stay still till be launched, if one enemy comes closer, must trigger the onhit and cancel the charge.

The trigger working for the instant cast version of the spell:

EDIT: I changed the spell properties, so now its easier and I already finished doing it, thanks ^^

Obs: I have timerutils.