Need some advise regarding Mintmark on XII Maravedis 1636 - Philip IV

Good day,

I have 2 counter stamped XII Maravedis with a clear 1636 stamp on it, below the date should be the mintmark.. 
The first one doesn't look like a letter, although i'm not a specialist.. ;) 
So then 3 options are open: 
- Coruña; shell  

- Segovia; acueduct

- Valladolid; shreds (could be ?? don't know how a shreds mintmark looks like..)


The 2nd one - 4th photo 

It could be a "C' - Cuenca.. 
But as mentioned before i'm far from a ‘specialist’.. 
And with a 0%  score @  the frequency not that sure anymore.. 😀
I have also one with the S - Sevilla, i'm 100% sure about that. that doesn't like this one.. 

Thanks for your thoughts.. 

Hello!

Mints and mint marks should be the same as here:

N#10352

Mint marks are usually below the (XII) value, as you can see in Numista example, or here (Coruña): https://www.monedasgallegas.com/felipe4.html

Valladolid mark should look like these:

Some VI and XII maravedíes coins can be found here (pp. 21-22): 

https://www.forumancientcoins.com/monetario-antiguo/Aproximacion-catalogacion-monedacastellana-resellada-sigloXVII.pdf

Thanks so much for the useful links & information.. ! 👍