The 27-D is arguably the rarest Saint now that more than a dozen 33s are known. In general 1929-33 are rarer gold coins (remember 1933 Indian $10 have always been legal to own, though expensive), though it is not universal. In general for $20 they are all rare, for $10, the 1932 is common, the 30-S and 33 are rare (none were minted from 1927-29), for $5 and $2.50, they only date minted in that span was 1929, and both of those are fairly common.