50 @ 23 = about 56lb at 25 right now without doing anything to it. Of course the tiller needs correcting but I'd be very gentle removing wood from the outer limbs (it does need wood removing). With a pyramid you want equal bend over the whole limb apart from a shade less bend out of the fades. Arc of a circle. For this tiller a tillering gizmo means you can't really go wrong....
You have very little room to play with to hit your draw weight at 27.
If I was tillering to 27 I would basically stop once I got that weight at 25 then I would shoot it a lot at the shorter draw. Check the weight after and you may then be at 26, a little final sanding would get me to 27.
Tiller is more important than hitting weight though.