Every server at Hetzner will get a native /64-IPv6-Subnet routed to that server. Besides virtual servers, an additional /48 subnet might be requested. Reverse DNS entries can be configured with the Hetzner robot. On this webpage you can also see the assigned subnet and the default gateway for your server. So configuring IPv6 is pretty easy:
# configure address
/sbin/ifconfig eth0 inet6 add <ip address from subnet>
# activate ipv6 routing
/sbin/route -A inet6
# set default route
/sbin/route -A inet6 add ::/0 gw <Hetzner gateway>
In case everything was configured correctly you can test it with:
# ping6 -c5 ipv6.google.com
PING ipv6.google.com(fa-in-x69.1e100.net) 56 data bytes
64 bytes from fa-in-x69.1e100.net: icmp_seq=1 ttl=56 time=8.40 ms
64 bytes from fa-in-x69.1e100.net: icmp_seq=2 ttl=56 time=8.64 ms
64 bytes from fa-in-x69.1e100.net: icmp_seq=3 ttl=56 time=7.97 ms
64 bytes from fa-in-x69.1e100.net: icmp_seq=4 ttl=56 time=7.94 ms
64 bytes from fa-in-x69.1e100.net: icmp_seq=5 ttl=56 time=8.36 ms
--- ipv6.google.com ping statistics ---
5 packets transmitted, 5 received, 0% packet loss, time 4006ms
rtt min/avg/max/mdev = 7.948/8.267/8.640/0.266 ms
If you want to keep that settings permanently, put all commands in /etc/rc.local
So there seems to be no problem with stand alone servers at Hetzner.