One OZ vs 9675 oz

[copperhead]

A $20 Liberty Gold Double Eagle is .9675 oz I realize being a currency has a set of benefits to it's own , but actual gold weight how much less gold per coin compared to a One Ounce coin
answer's in grams I will understand also
Thanks

 

[whay]

0.9675 oz=28.61238997265625 gm

 

[copperhead]

Understanding in the states, the mind set is Troy ounce
0.9675 is a $20 Liberty Gold Double Eagle $1,316.32
2.5 gram Gold Bar - Secondary Market $120.27
1 oz Gold Bar - Secondary Market $1,349.69
2017 1 oz Gold American Eagle BU $1,379.69

1 oz Gold Buffalo BU (Random Year)$1,394.69
China 1 oz Gold Panda BU (Random Year) $1,389.69

When purchasing large quantiles of gold is one best to turn a blind eye to many bullion choices
and focus on lowest price above spot or are there advantages to other types of gold purchases
that one must look past the Troy ounce standard