I have built a reproduction of a 17th Century New England Court Cupboard. I have cooked 20 or so batches of BLO and Colophony (pine rosin) trying to find the proper ratio of oil to rosin. My last batch had a weight ratio of 1 to 2 1/4 ,oil to rosin, and it feels like it is still pretty soft with an open time of about 4 hours. I am trying to reproduce this historic varnish, but I feel like I am reinventing the wheel. Does anyone have any experience with making a simple brown oil varnish?