[Twan]

Without informations about your nation, I can't see how people can give those definitive opinions.

If you have astral mages the cyclop of course don't need luck or ethearalness on items, just one mage or two to buff him. If you also have water mages, and plan to use just mages + cyclop he don't need quickness too (if you use the thug in an army, quickness items may be usefull, as mage AI isn't reliable to buff SC with a range 15 spell).

Anyway...

Behemoth boot + vine shield offer an excellent synergy (for a trampler vine shield or eye shield is far better than lucky coin IMO). But if he don't have mages to cast quickness nor haste nor flying on him (+ luck to replace the item), I don't think making your cyclop a trampler is the best use of the chassis (and the only way to give him quickness + trampling with items would create encumbrance problems, with the jade armor). So I'd use behemoth boots only if I have the appropriate buffers.

Horned Helmet reduce your defense for a negligible attack, you won't kill a size 6 ennemy SC, nor even an elephant, with it, and smaller ennemies are supposed to be trampled, so in general (if you are not fighting mindless) it's better to use an Horror Helmet boosting the cyclop's fear. Horned Helmet is only good if you also carry a weapon and plan to fight thugs/sc, it's main interest is one more attack to reduce ennemy defense.

Finally , if your goal is to kill a big army of chaff, using the cyclop as a mage and casting iron bane + blade wind x 4 kill far more guys than trampling, with reduced risk. And if your goal is to kill creatures able to survive against this (high hp, magical armors etc...), the cyclop would be better fighting with a weapon.