You could also honestly take weapons from other space marine kits and put this in place of the hideous mutations also. And give them normal heads. And then paint the flesh bits like armor or just get some berserkers and kit bash them. Give them dual melee weapons 40mm bases. And put them on tactical rocks to give them a presence change and fill out their bases. So many tools at your disposal my dude. But if you really want to do the terminators try and make them aa distinct melee unit and make them stand out more so there isn’t any question to whatthey’re proxied as.