More looper questions

[Rick Burnett]

Is there a way to pick a start and stop point?  I don't want one-shot here, what I want is for a loop to continue playing, cross fading into itself as it restarts, but from a start and stop point that I select.  

I've been doing some ambient type experimenting with the er-301 and I like to setup some kind of ambience from a longer sample.

Would be also nice to be able to module that start point, and have the end point either be a fixed point OR a relative distance.  Starting to sound like grain to me at this point of writing this :)