I do both air and antifreeze. I blow my lines with a bicycle pump (don't like the looks of what comes out of my air compressor condensate drain), fill with antifreeze, and again blow the lines. It is had to get all of the water out of the low lying places....the air can blow over top, leaving a little water behind. Better safe than sorry.
Chap , DW Joy, and Fur Baby Sango
2017 F350 Lariat CCSB, SRW, 4x4, 6.7 PS
2017 Grand Design Reflection 337RLS