Great comments. Thanks for that. Comparing the XR18 and L-20R, the XR18 is looking better for my situation. However, I'm a little confused about your comment I quoted regarding more outputs. I don't see two stereo pairs of line inputs, rather one pair of mono TRS line inputs. What am I not seeing here...
As it turns out, I have an iPad Air (128GB). I was looking at some apps to use for tracking, Auria, MultitrackStudio, some others. Would it be possible to use the iPad to do both functions, control and recording simultaneously? The USB recording bandwidth looks to be about 2.6 MB/sec for 18 channels.