Martin Logan Expression 13 - setup question

I have always had a soft spot for M-L speakers (owned the Quest Z and the Ascent) . I am tempted by the current Expression 13 but I have a challenge with the setup. Because of the depth of the woofer enclosure, I would have to put them within inches of the front wall. Has anyone had any experience with putting these speakers close to the front wall? If so, what was your experience with the rear-firing woofer? And If not, how big of a space did you have to leave between the rear of the Expression's woofer enclosure and the wall? Thanks for any input..

My alternative would be to get a pair of used Summit X, or to stick with more conventional options (Wilson, B&W).