Nice article. Regarding "under-trading" for larger accounts, I'd just add that on occasion it does make sense to bet large and take a big risk if you have a really good setup with high likely return and high probability of success. You usually can't have a 50-100% year by taking no greater than 1-2% risks. Rather, the 1-2% trades might get you a 10-30% year, and 1 or 2 home runs on size can bump it up to a great return.