more powerful.
to avoid the dirt issue, just use the ShopVac in suck mode and pull all the water out of each line

I would go around the outlets at least twice to pick up as much water as possible

That said, we winterize with antifreeze (so far in Maine, Scotland, Northern Norway and Germany ) with no issues.
I added a Tee with a valve at the water tank outlet, and such antifreeze form a jug with the main pump till all outlets run with the color of the antifreeze. then drain the system.

Same approach with the engine seawater side, although most of the antifreeze to is lost as it blasts out or the exhaust.

I usually recover about 2/3 of the antifreeze for use next year.

Blowing out sounds great, but I have had to repair too much plumbing due to hiccups in the system to use it. (more problems in cottages in Quebec than boats, but some in boats) It costs so much money and hassle to fix frozen equipment that the cost of the antifreeze is well worth it.