I have found eels will almost take anything including bread and sweetcorn at times. However luncheon meat is good (let it go off a bit) and maggots; I cannot use these in the rivers I fished as I always attract eels in the end and I am not fishing for them. But something a bit off and smelly is best if your targeting them. Bits of fish strip, a rotted banana paste that had gone black, I caught a load of eels on this once. I have heard pieces of slightly off liver are very good somewhere. Even a half asleep eel dormant in his lair in the daytime will catch a whiff of something smelly and want to investigate
Have you thought of trying the tidal bit of river you are near? At the right time these can be full of eels, cast a lug-worm in there or maybe even try them in the water you are thinking of fishing nearby; full of amino, guts and blood and scent; (I wonder if carp would take them or big Perch!!) scent is the key, they have a nose for anything smelly..
Any method will do, I always float fished and caught plenty with the bait on the bottom is best. There mouths are quite small really so smallish baits. I always know if an eel is on, the way they wriggle and wag their heads when caught, watch for snags, they will head for them.
I believe big gravel pits or lakes are normally best for the very big eels where they have resided for a few years and got big. Eventually they slide out and make there way overland on a wet night to find a river and back to the sea but I think they will spend more time in them than in a river where they have easier access back to the sea hence, they can be bigger specimens.
I have never got the idea they are such an endangered species, I always encountered plenty of them but most of my fishing has been done in river sections very near the sea, perhaps they just congregate there at times but I always found them an abundant nuisance. I wondered on occasions if an elver count really reflects the status of this species.; does it affect the amount that survive into adults? However, a very big eel is something worth seeing..It will be interesting to know how you get on.