As it's boat fishing the main targets will be spurs and thornbacks.
Although the water is deep there's not much tide so heavy weights are not really required, particularly up the loch from the boat hire location.
Fish tend to be bigger in the shallower water towards the mouth of the loch with more thornbacks down here. There are also a couple of marks with decent whiting and gurnards.
Most of the hire boats head up the loch where you're fishing generally in water around 100m deep. Braid is the main thing to use and rod and reels can be whatever you're happiest with.
I tend to us an Anaga with a large fixed spool for the retrieve.
Heavy nylon or wire snoods if you're targeting the spurs, keep the rigs simple to prevent tangles on the long decent. Lumi tube, beads and muppets can be productive.
Squid and all of the normal fishbaits including herring, mackerel and blueys.