The way I read your link, you want W2 and maybe W4.
The MoBo provides "term power", hence W2.
If the Micropolis is the first drive on the internal ribbon, W4 is unnecessary, MoBo takes care of the first device. Use W4 for the last drive on the internal ribbon.
General rule for SCSI I've used for years is first and last on a chain. That's Physical location on the cable/chain, not address.