For what it's worth.
I have the XTR Trails, 205mm(8")front, 185mm(7")rear. Not as good as the Formula The Ones they replaced, but a nice brake, good feel and modulation. Mine need a bleed, but even still, the front isn't powerful enough for me to do a stoppy in a hurry. Maybe get a Saint front caliper, and XT everything else. The beauty of Shimanno is you can buy any parts.
I'll consider swapping an XT caliper for a Saint if you wanna split them, just work out a cash exchange to balance it out.