selecting the correct uid
^I believe this answers my question...
(quoted from above source)
Newt:
"Actually I think the reason its not there, is because uid's aren't assigned until runtime.
Also there's no good way to guess the uid, because the naming method is shared between all objects.
What you can do is create the objects and place the uid into a instance variable, and then pick by that.
Or, you can pick by the sprites index "pick "nth"". This is unique to named object types, so all instances of the same object are easier to pick. Just remember the first is 0, second 1, etc. Then in expressions you can use sprite(index) to reference a specific instance, sprite(0).x would be the first created sprites x."
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More information here:
Scirra Manual
and
Understanding UIDs and IIDs
Sorry, just didn't know what to look for.