So, with a fine surface texture, I think the strategy is to get a lot of micro-contrast so that you get a extreme range of tones over a small area. That's what we really find appealing in a metal surface, right? Very fine-scale gradients of tone. Some of the most appealing metal surfaces (See Per's aluminum surfaces) have a slight dull graininess overall with micro-reflections of light that really add lustre. On the large scale, the micro-reflections add up to a kind of matte diffuse reflectance, whereas on the fine scale, you get lots of very quick micro-gradients. That to me is the appeal of a metallic surface... it's
not uniform reflectance e.g. from a mirror. It is a totally different direction than going for a uniformly reflective glossy look. If the surface reflects everything more or less equally then you get an overall 'wet' look... not really appealingly metallic, to my eye. Again I'd say Per is the grandmaster of this effect, check out his stuff and see if you don't agree. You can get the impression of rough, hard steel or foil-like reflectance, depending on what he wants to convey.
What pushing does is make the micro-gradients more extreme, introduce a bit of grain that (to my eye at least) suggests natural metallic lustre. Now, if I wanted a polished look, without lots of micro-gradients on the surface, then I'd shoot delta or tmax and amend my lighting accordingly. Actually, that reminds me, I have another moonflower shot with an entirely different impression (I think), it was on slide film and the general consensus is that it looks more like sandy landscape or an abstract figure... not metallic at all. But actually the lighting setup was identical. And right now I have before me another neg that looks, to my eye, more metallic. These are very versatile blossoms!
Concerning lighting, you could put a soft box head-on to the blossom and then you'd just get white, white and white, and maybe some grey

Overall the petals would be rendered essentially monotone. So shallow lighting is essential. Also rear lighting is something I use quite a bit with blossoms.
Now, moonflowers are a pill, the blossoms are moving as you shoot so if you have all manner of lighting setup (especially my cheapie tungsten softboxes!!!) you have to work very quickly. The things literally recoil from light. So... there's another practical reason to push, just so that you can get a reasonably fast shutter speed! Any moonflowers shots I've done, I had maybe 5-10 sec to get it done before the blossom was objecting to my lights. Magnolias are way easier!!!