Looking good! The buttons need to be made a standard size and shape so they look more like....uh...buttons.
If you want to use lead sheet to make buttons uniform shapes and sizes, a leather punch should be useful. This is a device that looks like pliers or wire cutters but it has a rotary head with different sizes of holes in conical punches on the head. You should be able to find them easily enough in a leather working shop, or a shoe makers or even on the internet.
If you want to use putty to make buttons (that's what I do), again a good quality metal punch set is needed. I bought mine cheaply from Amazon and they're pretty easy to find. They come in lots of sizes and you want one that does the smaller size of punches. The metal punch set comes with a thicker metal sheet with various sizes of holes. Projecting from the punch set metal bit are two columns. On to the metal columns you place the thinner clear plastic duplicate of the metal punch sheet. The plastic bit slides up and down. The third and last part of the punch set are metal solid tubes that insert into the various sizes of holes.
Roll a uniformly thin sheet of 2-part putty (MagicSculpt or Kneadatite or something like that) using an acrylic roller and a flat surface. An acrylic roller should also be available from art stores like Dick Blick or other places online. Cut a small section of putty that will fit on the metal punch. Put the small sheet of putty between the metal and the clear plastic and then insert a punch of the correct size. Result - a uniformly thin "biscuit" of putty which if you've gotten the size right can be used as a button.
Good luck!
All the best,
Dan
