I've resolved most of my issues thanks everyone (especially Khat your guides really are helpful to a first time casual like me)!

I bound
/tar Master
/Follow

and

/tar Master
/Assist

and bound a key to Interact with Target.

Then finally got the Oem3 mouse clicking to work decently when completing and accepting quests (woo!)


Only problem I have left is that occasionally only one window will respond to HKN. When I check the log it says it's sending to bot W1 and W2. I try reloading the script and restarting HKN but it doesn't help. I think it has to do with when I re-size windows with the mouse but I'm not sure. It's weird the keys will only send to the background window while the main one won't respond. Restarting the computer fixed but trying to get to the bottom of why it's happening and so I can avoid it.

Thanks for you help everyone.