Welcome to the forum. Your best bet would be to check out the library at JD's site which is
http://www.baseballglovecollector.com/1/?page_id=141 - you'll have to register but it's quick and easy.
That is super cool that Doak was your grandfather. If you read around this site, you'll see that many collectors have an affinity for his model gloves. I think there are some specific articles in JD's library as well about Doak gloves.