My next tests will be using 10% and 12% by weight resin. I would like to be able to do 8% by weight resin I just don't see how I can vibrate everything that well. I might test a piece to try it out. Anything over 12% by weight resins were just tests and not suitable, too much wasted resin.
I think that I will probably manage to get a good overall piece using 10%. I just have to take a little extra time to vibrate everything well and limit my pebble size to max 6mm (or thereabouts). I am no longer contemplating using the large jagged pieces as I had in my test samples. My next batch will be strictly quarts sand & quartz pebbles.