My goal is to get more bandwidth as possible. I didn't know that IPv6 packets are travelling in my network until I setup Pi-hole. Now, I do and would like to block them as that makes no sense in my setup where I do not have IPv6 at all.
I am a home user. My theoretical internet connection speed is low (compared to most) like 16Mbit download. Fact is I am not getting half of that speed on average. I have speeds less than 1Mbit at times.
IPv6 queries have ratio around 13% (~14000 forwarded IPv6 queries in ~107000 total) in two days of Pi-hole use. Even they do not resolve, they are eating some from the bandwidth. I am not sure how much.
There are a lot of IoT devices like Amazon Alexa, Smart TV and a like in the network that I cannot do anything to stop them sending IPv6 requests.
Moreover, linked thread was something that seemed to me already implemented in the system. Seems, my case is different after all.
I believe your calculation was something like below:
7000 queries / day, 72 bytes / query
7000 * 72 = 504000 bytes = 4032000 bits which is roughly 4 seconds over a 1MBits link speed.
On the other hand, my dig output above displays 67 msec real life query time (over I do not know what speed it was as it is really fluctuating)
67 msec = 0.067 sec.
7000 * 0.067 = 469 sec = ~7.8 minutes / day