Not once you get the hang of it. Actually the larger filler is easier when welding hot and fast as it acts as a heat sink.
Sam,
Not picking at what you chose to do, just adding a historical perspective. My guess is that your preference came from being unexperienced and trying to learn using too large of a filler with the RG, and that the difference you saw was due more to wire size than alloy ( and there is nothing wrong with that ). Im sorry if you were offended by the suggestion of trying something else, but I do still stand by it. If you want to try some RG-60 and RG-45 in 1/16 let me know and I will send a few pieces your way.