Hello sheepsucker, I do something similar, I use 1% risk and 2% depending of where my equity is regarding its moving average. If my equity is above moving average i keep going for 2% risk, once it drops below I use 1% risk ... according to my simulations, it improved my results by a big margin.
I have trading systems or edges if you will -- that after a winner or series of wins the historical probability of the next trade or next "N" trades being net winner(s) is still at or above the overall system average. I also have systems that after 2 or 3 consecutive wins the probability of the next trade or next "N" trades being net winner(s) decreases below the overall system average. Depending on your system logic there can be clear reasons why trades ARE dependant on what has preceded them. In the two distinctly different circumstances I would look to increase position sizing in different ways. A lot of systems fall into category 2 and that is one reason some position sizing strategies will perhaps let you down.