Question re: Disc or wheel cover

With a cover it petty much works the same (magnet on the spoke) unless the cover forces you to move your sensor for clearance.  Then you may have to glue the magnet to the cover itself.

I've never had a full disc, but I'd assume that is a magnet glue job as well.

I've got a Renn 575 disc.  The mechanic at my LBS suggested the method I use:  Apply a piece of wide electrical tape to the disc ( say maybe 2" x 2") in the area where the magnet needs to be and then use some silicone caulk to stick the magnet to the tape.  It  works well and the nice thing is that you can peel the tape and magnet off the wheel if need be without marring the surface of the disc.

The disc is some what narrower than my training wheel, so I have to adjust the gap between the magnet the sensor a little bit, but no big deal.  

Mark

On my TTR2 wheels the cover I made sits up on the rim so there is some space for the magnet under the cover, I didn't have to do anything for the magnet itself, I only adjusted the Garmin GSC-10 pickup arm out a tiny bit so it didn't rub on the cover where the magnet is.

On my new FLO 90, I've been looking at this.  I want to make the new cover sit on the spokes the whole way and butt up against the wheel fairing.  For this I'll either have to make a small hole in the cover for the magnet to fit into / stick out of or buy one of these magnets.

Hehe, that's why I use GPS. 

or just get one of these https://buy.garmin.com/en-US/US/prod517136.html - no magnet required and really easy to switch between bikes.

Yes.  No need for the sensor unless you want cadence but you don't need the wheel magnet to pick up cadence.

You will have to re-pair it with your Garmin but yes, it will work.