KEF LS60: Distance from wall behind them

It should not matter since they have DSP to adjust for placement.

I just set the LS50 W2 to wall mode, and it changed something -3 dB, not sure what. The LS50 W2 are 28" from the wall behind them. I imagine I prefer the sound now with that setting, seems a bit less colored

Don't know about LS 60 vs KEF Reference but FWIW always found speakers placed only a few feet from the walls behind them tend to sound flat imaging wise (probably with enhanced bass) whereas a monitor speaker usually had greater clarity and 'depth' of image when placed out about 4 to 5 feet from the wall but with some loss of bass (unless you found a bass node to set them in). That's the reason many folks use subs with small speakers. Try placing the 60's in the same place you have the Reference's and see if it sounds better (to your tastes) than so close to the wall. Its a trade off that I would vote for even if I had to get subs to flesh out the bass.

I have no problem setting the LS60s where the Reference 1s are now.  The Reference 1s are augmented below 80 Hz by a pair of Velodyne HGS 15s with acoustic room correction.  I assume there will be no problem using the subs with the LS60, but might bypass the crossover of the SMS-1 bass manager given the KEF Contact app has bass management.  Im not sure how Contact and the SMS-1 will play together.

How are you liking the ls60s compared to the ref 1s?