Hiya,
That's an interesting thought. I'd originally rigged it up as being relative for a couple of reasons - firstly, it meant that the player wouldn't have to worry about repositioning the crank between stages and messing up the initial turntable points, and secondly (and probably more importantly in my initial thinking), one of the thoughts I had early on was around having some stages where the turntables would rotate at differing speeds (basically turning at either double or half the speed of the standard ones). That said, I figured that the game was mean enough already without that, so I didn't actually do that in the end.
I've updated the uploaded build to have a three-way Crank Mode toggle on the title screen - just tap left to toggle between the three modes. The three settings there are Standard (the current relative system), Absolute, and Half Absolute. It does... interesting things to the difficultly. I suspect Half Absolute, where a full rotation of the crank rotates the turntables half-way, might be the mode to go for given the range of rotation you need to worry about - standard Absolute is way, way too twitchy. I suspect this'll probably make certain stages way easier, but given how nasty a few of the stages are, that's probably fine.