Are you sure about the 60 psf dead load? Is that due to the T&G ceiling or code?

The best match I can find in the tables are:

50 psf live
15 psf dead

SPF is not even in the table, too weak probably even if 2x12.

Southern Yellow pine on 12" centers:
#2 2x10 = 17' 5" span
#1 2x10 = 19' 5" span
#2 2x12 = 20' 5" span

Hem-Fir will not work unless #1 grade = 20' 5" span

D.Fir-L
#2 2x12 = 19' 8" span
#1 2x12 = 20' 9" span
Select Structural grade (special order) 2x10 = 20' 3"


I would consider eng. I-joists for this application.
i-level.com or search for engineered I-joists
These products come with free eng advice.