Depends if you want them on all the time, or just with high beams (what I'm going to go for, to prevent issues with beam alignment).
I was going to investigate if a micro fuse tap would fit in the fuse box, and take a feed off the high beam circuit to switch a relay, then turning the spots on. Saves pulling more current over the high beam circuit (although already fused at 15A, a 55W bulb pulls approx 5A) - essentially how the bigpie box works but for the high beam circuit instead (and not tapping a convenient connector).