Selected waveform region to new buffer size

I am selecting regions within a sample, stored in a buffer, via a waveform display and then patching the start & end points from the waveform display selection start & end outs to a groove object.

Great! I have a nice looping window to play with.

Is it now possible to adjust the buffer size to match the new start & end points defined within the waveform dispaly, so as to further edit & process my selected region? Of course, I would like my waveform selector to determin the size.

I also want to generate a single 'bang' each time the loop begins from its start point. I can't seem to find a real-time source for this. Groove loop sync out seems to spit out continuous DATA.

Any thoughts?