Ranged autoattack progressbar

[flupa]

I'm trying to make a bar that shows how much time is left until the next ranged autoattack is ready (very handy for a ranger). I only started looking at this UI stuff last night, so I know I need to play with it more. That said, I'm hoping some people can point me in the right direction.

First Issue:
There appears to be no dynamicdata for weapon delay, so I'll need to make an equation for it using haste. However, /gamedata.stats.haste shows the haste mod, not the actual haste which differs from the haste mod by the diminishing returns curve. Is there a way to retrieve the actual haste or will I have to try and approximate it somehow?

Second Issue:
How do I implement an equation? Right now the only example of a progressbar I've found is the bar for your breath while underwater. It seems the amount of the bar filled is based on one property:

DynamicData /GameData.Self.Breath

For the sake of experimenting to implement an equation, I tried to change the value to: "2 * /GameData.Self.Breath" (quotes only added here for clarity). But when I hit enter it changes back to the default value, apparently because an equation can't be used here. So how would I do this? Can I make a variable and assign it determine the progress of the bar? Something like:

Variable Wepdelay
Wepdelay = 9.0 * 1 / (1 + /GameData.Stats.Haste)
Barprogress wepdelay

Third Issue:
Just realized that I may need some sort of timer function to count down the delay. Is there a way to do this?

Any input is appreciated. I'm hoping I can do this through the UI. Otherwise I might have to make my own parse program to do this, which I probably won't attempt, lol.