ptpdprinter
Veteran
I've made 20x30" prints with the X100 and it showed some softness. It still was ok though if you are looking up close. The newest X100f would probably do very well at this size.
The new 24MP Fuji X100F has a sensor size of 4000p x 6000p, meaning the maximum print size at 300ppi is 13.33" x 20". To print 20" x 30", you would have to either upsample the image or print at 200ppi.