ok so
i went to post card teas and i went back to mei leaf.
And i found that post card teas had 3 teapots made by yanming himself. 2 of them were for staff to brew tea for themselves and one was for sale.
the one on sales was going for £20,000.
i phoned them first, and then i went there. over the phone the gentleman told me CZ hongni is less porous and muting becasue it has a glaze over the top. So i went to the shop in person. That particular gentleman was not there, so i asked the guys there about CZ hongni and porosity and muting. they showed me 2 teapot made by yanming, one was gifted to them by yanming himself and the other i cant remember. they were both smooth and had a gloss to the outside. The guys there said it didnt mute and it didnt seem porous at all. they were all orange in colour.
some of Mei leafs CZ Hongni teapots were made my master wu and some were non master pots. they were also smooth to the touch but not glossy. Don from mei leaf also seems to think that CZ hongni (or al least modern CZ hongni) is not very poros.
My teapot from yunnan sourcing is smooth to the touch but not glossy and it does not mute the teas. Becasue it doesnt mute i believe the clay doesn't absorb the flavours of the tea, and so it is not porous.
then there is the following article about master wu adding sand to certain caly mixes to increase porosity. i briefly skim read it, but it seems very informative:
http://tea-obsession.blogspot.com/2009/08/
I think the porosity of the clay must depend on the firing as people have said and also the clay mix. nowadays they must be firing the clay at higher temperatures.
and finaly mi Zini pot. one of the guys at post card teas said he knew the owners of the wan ling teahouse (award wining teahouse) personally and the stuff id very trustworthy. Someone said the pot i call zini looks like hongni, but i think it is zini.
the following article shows clearly what zhini purple clay should look like and mine fits perfectly:
http://www.thechineseteashop.com/manufacture.html