Closing and Keeping It Simple

[NullQwerty]

So, for the first time I'm thinking about closing the pool myself. I've been reading a lot of posts on here, but a lot of the setups don't seem to apply to me and are probably more complicated than I need it to be. Can you just verify that the below will work for me? I have a 24K IG Vinyl pool. One suction line (skimmer) and 2 returns. There is no Main Drain.

1. Lower water below skimmer and returns.
2. Disconnect pump and filter
3. Attach PVC pipe to hole in skimmer and attach Shop Vac to the PVC pipe
4. Turn on Shop Vac and let it go until no more water comes out of pipe that would have gone into pump
5. Pour 2-3 gallons of antifreeze down the PVC pipe.
6. Repeat steps 3-5 for return lines starting at the pipe that came out of the Filter (my multi-port valve will be set to fully open on one return line, and then fully open on the other, so that each line is blown out one at a time)
7. Put in Gizmo and screw on return line caps

If this works, just one more question. How will I know if the Shop Vac successfully blew out all of the water? I mean, if air starts coming out the other end, am I pretty much safe or could there be more water in the pipes?

Thanks a lot!