I cannot think of any real advantage in doing so. You would have to whip on a lengthy piece of leader material before tying the fly proper. The only possibility which occurs to me is that, if they are large enough and salt-water proof, you could whip on some heavy leader material and then tie on some white cock hackles for making up a series of perhaps six or seven "flies" for feathering for mackerel. Sorry not to be of more help.
Traditional salmon fly tyers still tie on gut eye hooks but I don't think many will tie the trout flies on them anymore. You could tie up some traditional wets with the gut leaders for display in a frame. Give them away to a maggot drowner or put them away because you might take coarse fishing up again one day.
Could you manage to tie on a spade end hook that's tied as a fly? You would need to leave enough hook shank behind the spade after tying the fly to knot your tippet.
You could use loops or tippet whipped onto hook shank before tying the fly. It does depend on the size of the hooks. If only small or fine wire then whipping on a tippet would be best. You would need a long tippet (3ft or such) if fishing the fly on point or short (6 inch or such) if using as a dropper.
Then it's down to your leader setup. If using droppers then best to have different sections of leader tied with tippet rings so you can add the short droppers. Then you would need suitable storage for flies with tippet, especially those for fishing on point.
spade end hooks for the long liners, spade ends have no VAT, I used to sell them to the Haddock liners, I still have a packet of size 16 square bend hooks, but I dont think I would tie a fly on them, the size 16 is much bigger than the trout sizes, easker1