If your Blackhawk is on layaway... why don't you just switch to a Bisley?
It's my understanding you can swap the grip frames, but a little fitting may be in order. I actually prefer the fluted cylinder, myself, but if you have another cylinder installed, like Hornetguy said... have a good 'smith do it!
I prefer the Blackhawk trigger and hammer, but I would swap them out as a set (if you were inclined to do so.)
I'm a Bisley man, I don't care for the grip on my Vaquero as much as the Bisley...
My pinky hangs off the bottom of the Blackhawk grip...
But the Bisley grip is longer and sets the hand at a different angle...
Side by side...