Hey Ken, as far as I can see there's no problem with your tubing for the wires - although the opposite might be more to the point. Over the years I've had to replace a couple cranks because the wires cut into them - - wires were OK, crank wasn't. Leadout wires are TOUGH, apparently they're quite a bit tougher than aluminum cranks. How I solved it (at least, they've managed to hold up now for almost 30 years) was to use one of the lipped brass tubes that you normally use for servo mounting. I drilled the crank hole big enough to take that tube, then folded the bottom (straight side) of the tube back. It rotates inside the crank hole, along with the leadout wires.
Seems to work just fine.