I shoot an airweight S&W regularly with everything from wadcutters to 200 grain reloads, and have a couple of ideas which might help. First, I have shot my guns accurately regardless of how high or low I gripped them. The only problem with the low grip, of which I am sure you are aware, is that they roll more with recoil and follow up shots are slower. Just practice dryfiring until you find for yourself how high or low a grip is condusive to accuruate fire.
One idea I wanted to pass along was to be sure your pressing the grip of your revolver into the web between your thumb and pointer finger. The gun will hammer your thumb less because it wil be in line with your arm. While I do use a two-handed hold for long ranges, I don't think its the most natural way to shoot. Once you you learn to naturally grip the revolver as described above, practice point shooting with just one hand for short ranges. Just be sure and grip the gun really hard when you do this and I think you'll be less concerned about always assuming a two-handed hold.