> SHA256

As it is, the size of that digest is also 14 bytes more and I don't feel happy truncating the hash. The bigger SHA2 versions are even longer. Considering that thing should go into cookies and URLs I did not feel very happy with that.

> You would indeed be better off using SHA256.

Probably. I was indeed under the impression that SHA2 is based on the same building blocks as SHA1 but I assume that is not the case. That being said: upgrading is not hard if it even comes to the point where it would be necessary.