Probably this will not help you much because I do not know any potters (except Korin)...but you posted a picture on July 23, 6:44 PM with a chop the one looks like it reads 万光 (First character may be wrong..
This could read Manki or Banki or even Banmitsu (But that does not sound right).
So maybe with your knowledge of potmakers you can pinpoint. Those chops in Reisho although not impossible, I just don't have time to try to look them up...
The hikari 光 kanji is common in boys name and is most often read Mitsu. BTW my boy's name is 喜光 Mickey...And the Shiyakusho or in this case Kuyakusho was definitely not guessing that reading, but it was accepted on the Kouseki Touhon as an acceptable reading for the name.