Mahoosive stack cancels out a lot of the reach, no? 390mm reach for a frame of these proportions, if anything would generally be considered a bit short.
I based the geo on my road bike that I've been riding for the last 4 years. So even though my road bike has a 57.5 top tube, they both have the same reach.
Curious about how the 60cm top tube will work for you.