Volume is more important than pressure when blowing out lines. You should regulate pressure down to prevent damage, volume is what moves the water out of the lines.
Is your water pump convenient to work on? I can take the tube off the inlet of mine and use one of the flexible hook up lines to draw antifreeze from the jug. With the water heater bypassed it only takes a gallon and 15 minutes.
As I normally drain the lines, blow the lines, fill with antifreeze and blow the lines again I would consider just filling with antifreeze sorta winterized, but good enough for that time of year.