depends on a couple of factors, but in general, metal on teflon on metal will be lower friction than metal on nylon on metal, but metal on metal with lubricant SHOULD be as low friction as metal on teflon on metal. the difference is, plastic is self lubricating. you won’t have to reapply the lubricant. if the lubricant on the metal comes off, you’re screwed. as someone who’s worked with ball bearings before (steel on steel), when you don’t have lubricant between the rotating thingy and non rotating thingy, your bearings explode. this is why bearings are often sealed or have some kind of lubricant retention system (or just extremely thick grease that gets all over everything and doesn’t go anywhere). in general, i’d go with some cheap nylon washers to play it safe, and add some silicone-teflon lubricant for good measure (surface roughness is not always ideal)