I noticed that after I became comfortable playing two handed and clearing most 12s was no longer difficult, my one handed passing ability got a huge boost. Difficult, dense charts are much easier two handed, obviously, and if you become used to reading them playing similar charts one handed is way easier. In other words, you will advance more quickly by playing two handed and playing (and clearing) hard stuff than playing one handed and trying to clear it, or playing things that are at or slightly above your comfort level. If you can read the chart the only difficulty is acquiring the physical dexterity to hit the notes.
Pinky scratching is difficult, but once you get the hang of it using both your hands falls into place quite nicely. I hope that made sense but yeah playing two handed will make you way better one handed even if it doesn't seem like it. | 
EMPRESSISONMENT 
