Data decay (time classification) is one of many classifications in k-NN search. You need to mirror all of them to achieve perfect dodging.
You need a lot more data than is available to estimate all weights, unless you want to get shot a lot.
I believe multiple people have noted that the weight on new vs old data is significantly more important than weights on other predictors.(In a gun) I believe Skilgannon said something along the lines of: I can change the weights by tenfold (except the one on shots fired) and I get very little difference in performance. So if you could match that weight in your flattener, you could (hopefully) get very low hitrates against you.