I've tossed a lot of oversize, bushy-as-heck flies on countless 0X/1X nylon leaders with varying results.

My best response to you is use a furled leader. The first time I tried a furled leader to chuck a big mouse I was flat stunned at just how much easier it was to false cast, how quickly I could accelerate my line, far fewer false casts to achieve the desired distance, and how much more accurate I could cast with a furled leader. I get mine from Cutthroat Leaders, but of course there's plenty of options. I have tried a few different brands, but I just like Cutthroat Leaders.

Try 'em once; you'll never go back to nylon.