I have my Profile 918's set to 'small', and crossed over at 100Hz. (still tinkering though)
When I had them at 'large', sometimes i felt the bass was bloated, especially with deep bass recordings.
The way i figure, let the sub do its job, and let the Focals do what they do best....mids and highs.
As far as the centre goes, it should be small too. If your AVR lets you set the x-over for different speakers, i would set it even higher...120-140. That speaker needs to focus on dialogue, no sense giving it the extra burden of mid/low bass.