Wow..thought this wouldn't be there and just went searching...wow it is there...Nice coins and top condition ones too... To give a small detail regarding these coins, as per the book by Mrs.Beena Sarasan, titled "Traversing Travancore through the Ages on Coins" 2016 edition, these are referred to as "Copper Tharam of Malabar and Cochin circa early 17th century. (pp 63, 69 - Coins 77, 87 and 104 later on).As per author these coins are depicting the influence of North Kerala consequent to the multiple adoptions from two branches to Venad as soon as it was dedicated to Sree Padmanabha (Lord Vishnu, as worshiped by Travancore Kings). Prior to this book being published most of the coin collectors were telling me these were in use in Northern parts of Kerala, especially Malabar area upto late 16th century.
As far as my knowledge goes, there are many varieties with varying weights (seems that weight is very much inconsistent, implying no use of a weight measure??). It is indeed very difficult to get heavy weight coins of more than 3 grams weight, and difficult to find both side excellent. I will follow up with a couple of my coins too..