I made a tip about shifting the start/end points here: Rytm tips and tricks - #206 by bgEN
And a track based on that: That RYTM 1.70 Sound - #259 by bgEN
The sample playback in Rytm works unlike other samplers I’ve seen. Once a loop is triggered, it continues forever in the background whether or not the amp is triggered. It will keep looping until another sample is triggered on the same channel, even if you switch kits. You can lay a trig down with SAMP on, but then do all sorts of stuff on other trigs with SAMP off.