Hi there GeordieDawg,
Welcome to the forum mate
You didn't say if you were fishing from a boat or the shore so I'll assume a boat
Three of us were at Etive just yesterday as it happens and I don't mind at all sharing information with a fellow angler buddy
It was our first time on the loch too so we only had what info we'd managed to scrape together online
Anyway, keep it simple, 1up-1 down rigs with as many luminous beads, booms, muppets etc as you care to mention......I was fishing with 3-4 x 8mm luminous beads right above the hook with a wee bit power gum to keep them there.
Short snoods to avoid tangles as the loch is 300-400ft+ in places, my top snood was only 6" and the bottom one below the lead around 9"-10"
Hokkai rigs and anything similar work well, again size 2/0-3/0 worked for us for fish ranging in size from the tiniest pout & gurnard to codling, ling, dogfish and much, much larger pollack & spurdog
Bait wise strips of squid, mackerel & herring on size 2/0 & 3/0 hooks worked well for us yesterday, something oily & smelly with the water being so black, visibility in the water is very low & you can only see a couple of metres down from the surface....if that?
Leads of 8-10oz, with maybe a 12oz if the current is strong, hold bottom no problem
Good marks are just off the quarry & the church down round the corner, we found mooring close to shore directly opposite the quarry was producing really well in the deep water there.
Here's a link to a wee video that helped us sort out, hopefully it might be of some use to you too
Loch Etive spurdogs
We are hoping to get another visit in before xmas but don't know if we'll manage, if not then as soon as possible afterwards for sure
Best of luck with the spurdog mate, it was only added to my species list yesterday too