If indeed J10CE has a ferry range of 2950 km (as per that one Avic promo material at Zhuhai) then not having a central tank might result in a ferry range of some 2500 km or so, give or take. That might still be enough for a quick recon glance performed at a 1000 km away, without using air refueling. Not terrific but also still usable for a wide range of potential target areas. (If J10C has a different actual ferry range, then of course final figures should be different as well)