Suspension loop in Evernew Water Carry

That's where I put mine. I also reinforced the holes with small grommets purchased from the sewing supply store. So far they've held up fine.

I put mine there as well. No reinforcements. They've held up fine.

I did the same. There are multiple points on the Evernew that appear ready for a hole-punch so a variety of choices.

What kind of cap do you all use for your gravity setups?

Not sure what Cap you mean, but I just use the one that came with the Evernew. FWIW, this is my 10oz “bells and whistles” gravity system. Great for groups or when convenience trumps weight. From left to right: Repurposed 2L Big Zip SL – Love the big opening and the hose attachment closes when the hose is removed. Male Sawyer inline adapter Sawyer Squeeze Female Sawyer adapter-GravityWorks Carbon Element-Male Sawyer adapter The right-most element is 2 Platy caps epoxied top-to-top with a big hole drilled through middle into which the clean bottle is screwed. Using variations of these parts it’s really easy to reconfigure for the specifics of a trip… – can swap out a 2L Evernew bottle for the dirty bag – Swap a Mini for the Squeeze – eliminate the carbon element Basically I can create anything between this full-on gravity setup and a 5oz uber-minimal 2L Evernew+Mini squeeze rig. –edited for spelling

A soldiering iron or a hot nail/tent stake can be used to put the holes in. This is done to all my platy bottles, and as long as I don't let the interia of the full bottle pull to hard, they haven't pulled through. The line can also be thread under a compression strap on the side of your pack to keep the bottle from flopping over. Steve