1.6 gpf is the most the law will allow in the US for new toilets. The only way you could get an old 3 gpf is from a private party or junk yard. However, you need to understand that all 1.6 gpf toilets are not equal. There a quite a number of cheap toilets commonly referred to as "builder grade" sold in discount stores. It is not the volume of water that is causing your problem, it is the design of the toilet and the mechanical parts. I would suggest a Toto as these have superior design. Either the G-max or the dual cyclone will get the job done as far as flushing is concerned. The advantage of the dual cyclone is the bowl rinsing is somewhat better. If you have a problem with skid marks, that might be the best for you. Otherwise, take you pick.