Faster ways to do Applescript loops?
 

I have two questions on this that I cannot seem to get right.

[CODE]
repeat with theTask in lstTasks
set the flagged of theTask to false
set the due date of theTask to missing value
set the start date of theTask to missing value
if the number of tasks of theTask is 0 then
set completed of theTask to false
end if
end repeat
[/CODE]

* What is the equivalent of a collapsed form ...

[CODE]set the value of {flagged, due date, start date} of theTask to {...}[/CODE]

* Does a faster way exist to avoid the loop, perhaps something such as

[CODE]set the value of {...} of every task in lstTask to {...}[/CODE]

The code runs. It just skips slowly through every task in a project list.