To use the twist assistant for harvesting in EQ2 try this:

Make 3 macros to cover all your harvesting abilities (or just the ones you plan on doing)

One macro would look something like:

/usea mining
/usea foresting
/usea gathering

Place the other abilities in the other 2 macros. Assign a key to target nearest item (I think it is called nearest item but maybe something a little different).

Now set the keys up in the twist assistant to:

* Target the nearest item.
* Press the macro keys.

After this you can just walk up to a node and the tool will target it and start gathering or mining for you.