At your top end, you are reading values at the rate of 100Khz (10 usecs per value), or only 200 instructions even with the Cygnal device. Sure if the '52 is just stuffing out byte data you might just get it, but even a byte fetch takes two instructions or so.

I see your point about having lots of prestored data points in ROM for you to pick and tune with. I increasingly think that you need a state machine !

Steve