Try Stymphalian Wings. Their fear comboes with the gold shield, they make the golem an offensive powerhouse even with two shields, clock horrors are size 1 so extra trampleable, and they'll give the golem flight to go back to the lab for another go that much faster.
Only downsides are the cost (each pair costs your a golem, basically), and the encumbrance of spell casting + trampling so you probably want to add a recuperation pendant and/or boots to the kit, and script a "Hold" or two before you attack as well.
Also, give the golem a Pendant of Luck, it's standard thug equipment for a reason
ETA : oh, and whatever you decide the Black Steel Full Plate is naff. Super high encumbrance (remember, spell casting encumbrance is double that !) means by the time your golem gets to the end of his script he'll be so tired even a militia could crit him to death, and of course he'll fatigue himself even more hitting dudes. The only use for Black Steel is on undead who don't care about combat encumbrance.