Then go with FastJack's, it's simple enough, it works well enough, and has the least book keeping.
Of course, the RAW I came out with is also pretty darned simple, it just means writing down an ECCM score for each of his drones, then when it's hit, he looks at Signal, adds ECCM, and has his answer. And buying an ECCM prog for each drone, but that's a few dice rolls (or, for simplicity, a hand-wave) and some nuyen out of his pocket.
Unless all his drones have the same Signal rating, he has to look it up and add his ECCM anyways, so it really isn't much more book keeping to go by the RAW. Either method, you still have to track it as a program running on the drone (at least, when the techno isn't there). By the method I laid out, it always counts, by FastJack's method, you have to add / subtract a program and redetermine response every time he jumps into a new drone.
Both have pros and cons from a minimal book-keeping standpoint, and I hope I laid them all out. I lean a little towards my interpretation of the RAW over FastJack's method, but then again, I'm me, of course I'm going to think my idea is better.
Also, I'm sure that this isn't an exhaustive list of pros and cons, so people, please, pile on the ideas and help out a poor Dead Monky speed up his game!