My name is Ken and I am new to the fascinating culture of Zisha clay pot tea brewing. Whilst I've always drank Chinese tea since young, I am just beginning to learn and educate myself on the knowledge of this subject which makes it all the more interesting.
The attached photos so a teapot that was gifted to me from a family member a few years ago but I have only had the chance now (during lock-down) to actually start using it to brew Pu-erh.
I have a few question that hopefully someone with superior knowledge to me can help answer.
Whilst I don't doubt the authenticity of the teapot, it would just be nice to "know"

Questions:
1) Handle:
The teapot is Xi Shi style, with a thicker bottom part of the handle. I understand this style is traditionally held by grasping with the whole hand and drinking directly from the spout. I have noticed that the handle is curved. from the top of the handle, it sways/bends left whilst going down - see photo 1. is this a design feature to make grasping it easier with whole hand? or perhaps this is a sign of poor craftsmanship and is a flaw?
2) Potters Mark
Looking at the potters mark on my teapot photo 2- I am unable to match it to any of the marks shown in the catalogue it came with or the certificate it came with. Why is this? am I just reading it upside down

why are there so many variations of the marks shown in their catalogue (photo 7)?
3) Certificate - photo 3
I know certificates can also be faked. But I was looking at the back of my certificate and you can clearly see the ink of the writing has lighter and darker spots - indicating it was truly hand written. is this a good sign to judge that this is not fake certificate (and therefore teapot) assuming that if it was fake it would have just been mass printed off a printer/computer. I wouldn't imagine a faker would bother to hand write a fake cert?
4) Potter's info - Chen Hua Song 陳華松
I have tried to research more on this potter's craft online but have been unsuccessful. Does this mean potter/master is not too famous? any insightful or further info would be appreciated.
I would have posted more photos but 3 is the max

Many thanks in advance
Ken