I set notes 0-6 to play the default notes on the respective voices with the drum pads and the rest play notes on the active track from the keyboard. Works both while playing and recording. Very happy with this setup.
I did something similar for the 606. I borrowed one from a friend and tried to make a kit with a similar feel. Here are back to back clips; the first is the LXR, second the 606. The levels are pretty low.
@brendanclarke, fellow physicist here although I'm in a totally different field (thermoacoustics). Read the paper and it looks like a fun project. Good luck with the thesis. Writing mine was a brutal experience.
Does the step quantize have an effect? I was having trouble with this as well and lowered the quantization down to 1/8 for 1/8 rolls. It seems to work better now but I'm not sure that it's not that I'm just better at hitting it in time.