I don't use a scale. I mix very close to 50/50. The "B" side is a little heavier than the "A" side.
Let's say you have 1 fluid ounce of "A", I put About 7/8 fluid ounce of "B". And have even made it 50/50.
The only time I have a problem is not mixing it long enough.
Remember, you have 6-7 minutes open time and although in your mind, you have to hurry, if you work steady and don't stop, 6 minutes is a long time.
My rule in the shop--When a power tool is running, I do not look up or talk to anyone until the tool is OFF. The same when once the "B" side is poured into the "A" side. No distractions until it is the pot.
Thanks, Gary