Field luster is the first thing that disappears at AU-58 because the fields are the highest points of the design. That is a starting place which will set the coins in either AU or Mint State. MS-60-63 coins can look rough since the contact marks are high up and in focal points. This design does not come flashy with high luster like most other series, so Gem and up are graded mostly on hairlines and field marks rather than original flash.
For your coins, I would grade them AU-58 and AU-55 respectively. I see no field luster but there is significant sharpness in detail.
Suffering from bust half fever.
Want to learn how to attribute early half dollars by die variety? Click Here:
http://goccf.com/t/434955Shoot me a PM if you are looking to sell bust halves.