"Just a suggestion:"

Obviously it would have been easier to copy and past the link. I copied the specific pages into PDF with the intention of adding to my report.
It wasn't until the next day I decided to post it here and didn't feel like searching for the site again.
But I'm glad you were able to find it.

"Can all or part of the line be rigid pipe?"

The problem in my pic is there is huge vertical rise with 3/4 pvc. I don't think it would make a big difference if the pipe is rigid or not, but it can't be larger than 3/8" at least until it turns.
You wouldn't think the pump is designed to push a 3/4" column of water 8'.

Now the reason I put loops in the 3/8 line years ago may very well have been due to a failed check valve. I actually hadn't given that much thought.
With the tube being clear, you could see water drain back when the pump cycled off causing it to start back. So, I put a loop in it and no it didn't siphon back ( that's field vs. theory).

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