I am looking into purchasing some older property (1956 built). This property has the old two prong plug outlets throughout (16),and i want to change them to 3 wire outlets. So, far i am told i have 3 options to do this. 1. Re wire the building (not in my budget) 2.Install GFCI breakers (for this type of breaker panel GFCI breakers will cost and arm and leg,and if they even make GFCI breakers for FP panels or ever did. 3. Install GFCI receptacles at the first recep. so as to protect the other receps. downstream. The problem here is that on a given circuit there are receps. that are located in different rooms.I can envision that running into a problem. Would putting GFCI receps. at every location be the most effective for this issue? The existing outlet boxes are metal and measure 2-1/4"DX2"WX3"H.