Flying inbound to the beacon, adjust your heading so the blue nav aid needle is on the green course bar, i.e. on the hold axis, and the magenta diamond is on top of that. You have now found your single drift value aka the WCA. Mentally double or triple that value to come up with the heading you need to fly outbound on.
Is it not as straightforward as making sure (on the outbound) that the magenta diamond is a third of the way (the angle) from the lubber line to the course pointer? If the magenta diamond is closer than that to the course pointer than that, drag it away (i.e. turn away from the course pointer). If it is closer to the lubber line, turn back towards the course pointer.
Using your example, outbound track 180:
Lubber line on 150, magenta diamond on 160, course pointer on 180 is spot on.
Lubber line on 160, magenta diamond on 170, course pointer on 180, turn (left) away from the course pointer.
Lubber line on 140, magenta diamond on 150, course pointer on 180, turn (right) towards the course pointer.
I wish I'd had a magenta diamond when I was learning to do this!
