Not to be dismal,but the thumb safety is fitted to allow no movement of the sear.Change the hammer and or sear,likely you will be fitting a new thumb safety,too.
I think it is Wilson that makes a semi-drop in beavertail grip safety.You might be able to bob and shape your spur a bit to work with one of those.They do not require radiusing the frame.You may end up doing a bit of blending,and,you will have to fit the grip safety,for function.You will get to retain your original hammer/trigger/sear/thumb safety fitup.
I have found theCylinder and Slide hammer/sear/disconnect sets work out pretty well for me,if you do go with a commander style hammer.If you need a thumb safety,I like the OEM Colt.Midway handles parts,too.
Without meaning any disrespect,how all these parts work together can literally be a matter of life or death.You do not have to be an exceptional person to work on one,but you do have to understand how all the parts work together.The job you are considering may require some special tools,its a good idea to use a proper sear jig and stone if you must stone the sear,etc.
To end up with a safe and functional pistol it may take an investment of time and study,some extra parts for do-overs,at least a Kunhausen manual,etc.
Any local gunsmiths you trust?