I want to add VPN, DNS to Tails to increase anonymity, but is it better? Or does it get worse?
VPN’s do not increase your anonimity and only increase attack surface. Also in tor, all your dns quarries are done by your exit node, so there is nothing you have to configure there.
OK. Anyways, Do you opearate site?
In general your anonymity gets worse, to quote the first link,
Some users have requested support for VPNs in Tails to “improve” Tor’s anonymity. You know, more hops must be better, right?. That’s just incorrect – if anything VPNs make the situation worse since they basically introduce either a permanent entry guard (if the VPN is set up before Tor) or a permanent exit node (if the VPN is accessed through Tor).
Similarly, we don’t want to support VPNs as a replacement for Tor since that provides terrible anonymity and hence isn’t compatible with Tails’ goal.
See also Why you should NOT use a VPN with Tor.
Couldn’t have said it better!