Besides interior volume, the sizing can effect how the pack rests against your back and the positioning of the loadbearing straps. Go with what they recommend.
17 Korua Apollo . 17 Lib x Lost Mayhem Short Fat . 17 Jones Storm Chaser . 16 Never Summer Swift . 14 TJ Brand Retro Fish
17 Burton Malavita Wing . 16 Burton Genesis X
16 Flow Talon