Im doing things at 140 bpm at the moment which makes 1 line 107 ms, so when I want to do half line delays its inaccurate. when I try to put 53.5 milliseconds in the delay time box it rounds up to 54 ms. will there be an update of the delay allowing fractions of a millisecond in future versions?
Check Line Sync and then set the Offset Parameter -50%?
http://tutorials.renoise.com/wiki/Audio_Effects#Delay_Devices
Nice one!