setting up on-board openvpn server w/pihole question

[Jumpstarter]

I have setup nat table rules to control the interface of the router VPN server
piholes ip is "192.168.1.2"
iptables -t nat -A PREROUTING -i tun21 -p udp --dport 53 -j DNAT --to 192.168.1.2
iptables -t nat -A PREROUTING -i tun21 -p tcp --dport 53 -j DNAT --to 192.168.1.2
iptables -t nat -A PREROUTING -i tun22 -p udp --dport 53 -j DNAT --to 192.168.1.2
iptables -t nat -A PREROUTING -i tun22 -p tcp --dport 53 -j DNAT --to 192.168.1.2

Also, I have setup push "dhcp-option DNS 192.168.1.2" inside the server settings.
I did not want to manipulate connect to DNS automatically option. left it at default Yes
Are there any options i need to consider for conditional forwarding and reverse lookup?


EDIT:
Decided to switch to

iptables -t nat -A PREROUTING -i tun21 -p udp ! --source 192.168.1.2 ! --destination 192.168.1.2 --dport 53 -j DNAT --to 192.168.1.2
iptables -t nat -A PREROUTING -i tun21 -p tcp ! --source 192.168.1.2 ! --destination 192.168.1.2 --dport 53 -j DNAT --to 192.168.1.2
iptables -t nat -A PREROUTING -i tun22 -p udp ! --source 192.168.1.2 ! --destination 192.168.1.2 --dport 53 -j DNAT --to 192.168.1.2
iptables -t nat -A PREROUTING -i tun22 -p tcp ! --source 192.168.1.2 ! --destination 192.168.1.2 --dport 53 -j DNAT --to 192.168.1.2