Thanks again perf12! Now the 70c had much more obvious differences.
So I've checked mine, and something seems odd... I have 15 copies of 70c stamps, and only 3 of them have the cut corners as indicated for Type I above - the remaining 12 all have sharp corners, as Type II. However, the catalog value for Type II versus Type I ( 32€ versus 0,1€), makes me think I got something wrong? Seems unlikely I should be fortunate to have that many of the much more valuable type and only a few of the common type?

Could it be opposite?