You can tap into the daylight circuit, but then the spot lights will only work when your High beam is on. I bought a RE switch from a member on the BMW Club Cape Town (Kim Heptinstall <
kim.heptinstall@tess.co.za>). This is a 3 channel relay Switch with "dip switches" on each channel where you can chose if you want power to your accessories only if the ignition is on or if there must always be power to the accessories. I connected my spots with a inline handlebar switch and set the dip switch so that the spotlights will only come on a couple of seconds after the ignition is turned on and it will switch off a couple of settings after the ignition is turned of. I the also have the option to switch the spot lights on and of from the handlebar switch. My GPS and the 12v power socket is connected through the RE Switch so that there is always power on it. Each channel on the RE Switch have its own fuse as well. The switch cost me R700 if I recall correctly and Kim will supply you with all the necessary cables, isolation tape, cable ties and also a very easy DIY installation guide.
The cheaper option is to buy a spotlight loom with relay and switch from Midas/Autozone and connect it to your spotlights. I prefer to be able to switch my spotlights on and of on its own and not via the brights.