As a long time owner of many SF speakers (Gp home, cremona auditor, cr auditor m, Guarneri homage and than couple from Franco Serblin's new company, Lignea and now Accordo) and by looking the size of your room, I would strongly advise you to choose smaller speaker than many has suggested, meaning 'monitor' on the stand, instead of full range sized speaker. Furthermore, there is a brick and mortar dealer of SF and now Franco Serblin's speakers in my home town and I have had a chance to extensively listen many of their designs, including hearing the 'inside' impressions from experienced personal. (for examp. Olympica 2 is 'no no' model in their line up.
My room is aprox 12x18 and have enough space behind and on the sides, the furniture is not on the way, have no problems with waf factor and still thought that Guarneri is a bit big (if you want really to hear what that speaker can play, in terms of stage and positioning on it) for that room. Yours is slightly larger, but I would be very hesitant to put 'big' speaker in it.
I am quite certain that (for the same money) you may buy smaller, but 'better' speaker and more importantly, one that suits your space more. If possible, would also advise you to hear few models of Franco Serblin's new company, like Accordo, Accordo Essence or perhaps new Accordo Goldberg. Since Franco Serblin is creator of Sonus Faber, you should not overlook his newer designs as imho, he is the 'real deal'.(aldo Essence and Goldberg are made by his son in law) Not to take anything from SF of today, but still...Electa Amator 3, Maxima Amator or perhaps Guarneri (Serblin's older Memento or perhaps newer Evolution) are also fine choice. Best of luck in your search