Garmin spares

By magic I am now the owner of a 910xt, and a single cadence/speed sensor, but only one spoke magnet.

Before I go doing all the leg work, are there any awesome places I should know about for spares?

I would like another two s/c sensors (to kit all three bikes), and I deffo need the best magnet options for crank. Gonna look for the quick release kit too.

Can't see HHV getting upset about the sensor (hear all the others' machines beep as we set off on a lap) but really I want the most secure setup for the track, where the road bike can be a bit more flappy.

I'm also thinking of buying those tiny magnets that attach to the inside of the pedal hole in the crank arm, rather than have the addition zip-tied thing. Anybody using them?

I use the magnets, never had a problem with them

Yeah the rare earth magnets that grab the back of the pedal axle are fine for track

Edit: did some research for magnets.

Depends on your set up. I have a gap between the magnet and sensor of about 6mm and it works consistently.
Something like these.
http://www.ebay.co.uk/itm/5pcs-12mm-x-5mm-N50-Grade-Strong-Small-Disc-Round-Rare-Earth-Neodymium-Magnets-/371021203241?pt=LH_DefaultDomain_3&hash=item5662964729

Thanks. Sorry I just edited the last post after doing a bit of research into neodymium's. I think I'll grab 12x5's (or 12x4) but from a UK seller. Don't mind paying £2 for impatience.