you might buy 2 New chainrings in 110 bcd in the sizes you want for one of those 50-34t cranksets ..
I , in the 80's, bought a Campag Mountain Bike [discontinued] crank, I got it with a 52,42,26t chainring set ..
they used a standard 5 bolt pattern, like Sun tour/Shimano then..
proved to be interchangeable with the M730XT. same BB.
Its on my Loaded tour bike.. Campag Olympus Rt side actually heavier than the M730 arm
[ now running a 50-38-24]