There is defensibility on other grounds. Adequacy doesn t matter. Context, however, can lead to pretense. Disparity between amounts gives pause only if context makes it looks like a sham. Exchange is nominal.
Bargain makes consideration sufficient.
Thomas says that silver dollar is a pure myth. But depends on intentions of parties if they believed that there was a dollar. Could be valid K if at time of K parties believed it was possible. Consideration doesn t suffice if disguised gift if they both know it doesn t exist. There was a bargained for exchange though a difference in value.