Do you delete every other frame instead of capturing every frame? I'm not sure if that could help but it's worth a shot. And have you saved them as 'Adaptive' and 'Pattern' (instead of 'Custom' and 'No Dither')? Also, I save mine as 'Bicubic' instead of 'Bicubic Sharper'. I'm not sure if any of that might help but if it doesn't, let me know and I'll ask around with some other gif folks.