I'm a plumber, and yes the spanner flange works! I slide the spanner under the flange, and in an old house the hole for the drain is too big or the wood is punky but what I have been using a lot!!! is a flange extender that will drop in the pipe and there are three allen screws that you tighten and causes the extender to expand and become water tight . also if the wood is good you can use what we call a johnny bolt" its a wood lag on one side and a machine screw on the other I know,,, too much info!!!!!! but,, allways use brass closet bolts and allways bring extra wax rings!!!! rings work on bow strings too!! I hope you do fine!!! we'll be with ya!!!!! Jeff W