I think improvising in this kinda context is very difficult, to be honest. I spent months practicing this kinda thing, and the recordings are pretty much all snippets from that. I never knew when a good idea was going to come, so I'd just plug into the computer and record everything. I found it helped to have an idea of what I wanted to do. As an example, I remember for the first track I wanted to set up a majorish sounding motif, and see how long it would take to shift it into minor. I used a DL4 on the recording, and I was really happy with the ghostly sound of the loops as they decayed.
A guiding tempo would have made things more difficult for me, though. The DL4 was pretty much the only equipment I used, and it doesn't have a metronome or any way to sync up to a rhythm track. As it happened I liked the surprise of looping out of tempo, and not knowing how each new idea would work. Sometimes you'd get really close note clusters, and I always enjoyed them. Since then, I've gotten a Boss looper that I run at the same time, deliberately out of sync. It almost feels like random harmony is being created. But that's an idea for EP#2... :-)
But anyway, thanks for listening to my music. It really means a lot to know I'm not the only one who likes it! :-)