There are actually two different main sets containing 39 stamps total. Scott does not provide correct information regarding these stamps.
The 1935 set of 18 contains Scott 219-225,and 11 values from definitive issues prior to that. They are Michel #1-18 valued approximately $1300.00 mint ($625.00 hinged) and $500.00 used. Note that forgeries exist, so authentication is required.
The 1937 set contains 9 values. Two of the values come with two types for a total of 11 stamps. This set comes in regular gum (11 stamps) and grilled gum (10 stamps). The set consists of Scott 227-229b; 231-236. I did not give the grilled gum Scott numbers. Scott only notes that #232 comes in two types. These are Michel 19-27 with the type 1 stamps. Type II stamps are 21-II and 23-II. Values for the set with Type I regular gum is approximately $450.00 mint (225.00 hinged)and $150.00 used; grilled gum is $390.00 mint ($175.00 hinged)and $150.00 used. 21 Type II regular gum is $5000.00 mint and $4500.00 used, grilled gum is $45.00 mint and $25.00 used. 23 Type II is only on regular gum and is $120.00 mint and $20.00 used. Again, forgeries exist, so authentication is required.
With the catalog values, unless you have certificates with the stamps, there is a good chance you could have forgeries, especially since there were only 50 of 21-II made with regular gum. My Michels are a bit dated, so the values may have appreciated a little since then.
I recently came across a set of 29 stamps with the "9-Hole Cross" circa 1935 Swiss "First Officials". Can our fabulous SOP membership point me in the right direction to find more history and value behind these stamps?
Many thanks in advance
re: Swiss 9-hole Cross
There are actually two different main sets containing 39 stamps total. Scott does not provide correct information regarding these stamps.
The 1935 set of 18 contains Scott 219-225,and 11 values from definitive issues prior to that. They are Michel #1-18 valued approximately $1300.00 mint ($625.00 hinged) and $500.00 used. Note that forgeries exist, so authentication is required.
The 1937 set contains 9 values. Two of the values come with two types for a total of 11 stamps. This set comes in regular gum (11 stamps) and grilled gum (10 stamps). The set consists of Scott 227-229b; 231-236. I did not give the grilled gum Scott numbers. Scott only notes that #232 comes in two types. These are Michel 19-27 with the type 1 stamps. Type II stamps are 21-II and 23-II. Values for the set with Type I regular gum is approximately $450.00 mint (225.00 hinged)and $150.00 used; grilled gum is $390.00 mint ($175.00 hinged)and $150.00 used. 21 Type II regular gum is $5000.00 mint and $4500.00 used, grilled gum is $45.00 mint and $25.00 used. 23 Type II is only on regular gum and is $120.00 mint and $20.00 used. Again, forgeries exist, so authentication is required.
With the catalog values, unless you have certificates with the stamps, there is a good chance you could have forgeries, especially since there were only 50 of 21-II made with regular gum. My Michels are a bit dated, so the values may have appreciated a little since then.