Note: I'm not really too interested in optimizing, just understanding the baseline. Though TWF loses in both categories.
Some of your math isn't correct.
2d6 with GWF is 8.33. It's AVERAGE(3.5,3.5,3,4,5,6)*2 in excel/google docs.
1d10 with GWF is 6.3. AVERAGE(5.5,5.5,3,4,5,6,7,8,9,10)
TWF...