FWIW Raceface provide spacers, and a handy little chart, with their version of the Hollowtech BB.
I needed them when building up the InBred. The BB shell was too narrow to fit the crankset on it's own, sans spacers. I didn't use the Raceface BB, but used a 105 instead (apparently the RF ones are bobbins and break after only a few hundred miles, so I was playing safe rather than sorry). The problem is that the BB external cups on a 105 BB are wider than those on the RF one (which could go someway to explaining why the RF ones are pants). So the standard spacers wouldn't work, as they only provided 2.7mm ones(IIRC), and I needed 0mm on the NDS and 4mm on the DS (so that the middle chainring didn't foul the chainstay). I visited my LBS and they gave me 2*1.5mm and a 0.7mm which did the job nicely.
And yes, they go between the external cups and the BB face.