My side project tries to give secure default settings for all major webservers and other software (like haproxy, mysql, mailservers etc): https://cipherli.st/

From the start it has listed the suggestion to set up >2048 DH keys.

If you want to test your site for export ciphers, you can try my other side project: https://tls.so/ - you can also use the SSL labs test but mine is faster for just testing ciphersuite. (And it's open source, so you can use it internally as well).

Mozilla also has a good wiki page for SSL settings: https://wiki.mozilla.org/Security/Server_Side_TLS