One thing you may want to consider for the bad parts (bent parts) that you
have made is to whack them with a hammer. I often do thin metal work with
tin snips and a gentle striking of the edge area afterwords cleans up the
edges of the metal very nicely without deforming the rest of the sheet. In
addition, curved pieces often respond very nicely when they are placed on a
flat piece of metal and struck firmly and evenly with a hammer.
Rule dies work on very thin metal (on the order of tin foil) but anything
thicker and the edge becomes dull very quickly. That is the time to go to
full dies and those can be a real bear to do if you want a full cut piece in
one step. Often just dividing up the cutting so that a center hole gets
punched first along with a pair of alignment holes and then going on to
other partial punches that have the alignment pins and punching the rest of
the part is the best way. For example, punch a full round and then shear
off a part of that round to make the half moon part.

--
Bob May
Losing weight is easy! If you ever want to lose weight, eat and drink less.
Works every time it is tried!