HED 3 wheels and bike computer

I have used both electrical tape and super glue. Both work fine. If you are the paranoid sort, I'd go superglue... otherwise, the tape is fine alone.

I don't race long course, but I can't imagine why you wouldn't use your cpu in an IM...

I don't own a bike computer, per se but I do have a 910xt.

1st IM: heart rate and time only

2nd IM: Used most options on 910xt but not speed or cadence on the bike.

Super Glue GEL.

GEL is way better then regular super glue which is brittle and does not flex.

I've got a magnet mount that uses a zip-tie, but I also epoxied it in place.

One suggestion:  Temporarily mount the magnet to make sure it is close enough for the sensor to pick it up.   On standard wheels the spokes taper from the hub to the rim, but on HED.3, there's no taper, meaning the the HED spokes near the hub are farther away from the fork.  If your sensor is sensor is currently mounted between the hub and the midpoint of the spoke, it may be too far away from the sensor.  I had to play with the location of my sensor a little bit so that it would work with both my Shimano training wheels and my HED.3 race wheels.

Mark