A first step would be confirming that the mating is impeccable. Mating that is slightly off will rob power. Second on my list would be to experiment with hammer filing, using small grits. I use strips of micron graded sanding film, and I would be going 30/15/9 in micron size of grit, which is more or less equivalent to 500/1000/1500 in standard sandpaper grit. This can tend to increase felting on the striking surface (in my mental image), and makes for crisper attack sound.
I don't have much experience with CFX in particular, but for needling up in power, I like a technique I learned from Terri Otake of Shigeru Kawai, which involves one long needle aiming from mid-low shoulder upward toward the molding/crown. It is easy to experiment and see if this is going to give you anything. For the side toward the shank, the Renner needling tool with the cut outs for finger and thumb gives you access for the right angle and for enough force to inset the needle.
And, of course, there are regulation parameters that might be in play, but that would require getting inside the head of the pianist, asking questions about specifically what is meant by bringing up power: in what context?
Regards,
Fred Sturm
"The true sign of intelligence is not knowledge, but imagination." - Einstein