Mr_props @Airsaber. Hi! FUD doesn't need much sanding, and 800 would be a better choce, probably finishing with polishing cream. But i guess you ordered the White strong and flexible which is a little tedious to sand, so i would use 400. But that's a fair choice since this material is very sturdy. You may find it interesting to use a car body primer (like styrene based) to fill the deepest holes before sanding. In this case please make sure you got rid of all the printing powder first, as it would be glued by the putty. You can get this product either as a spry, or something to mix with solvent to make it more liquid and dip the pieces inside. If you'd really have a semi glossy white plastic, of course, you can't use that at all, and sanding will be the only solution i'm afraid. That's why i prefer FUD: If the pieces stay about 24>48h inside white spirit, they become white (but still slightly transluscent). However, it is not possible to control how white they get, and it can either affect a thin layer of the surface or the inside aswell depending on factors i didn't fully understand yet. The wire you suggest to use is something i use myself, but i feel like the result has some kind of elasticity i don't like too much. I'm not mostly using annealed aluminium. It breaks relatively fast in comparison, but it is very mobile, and tends to keep the exact pose given. Now your choice would be more durable i you used 0.3/0.5mm steel wire, as it is more resilient than copper or aluminium. It is also affordable and way easier to find than annealed aluminium wire. I hope i answered your questions, please feel free if i didn't. Good luck, and thanks :)